"Take secrets to the grave" is not exactly a new concept.

Much of the worth of humanity is what is inside the human head, and that is frequently lost to the world, whether it's a great writer dying before penning his last book, a smith who could make something no one else could, or a mathematician who hadn't written down his proof yet.

I think there are three major reasons:

1: You can't buy and sell much with actual bitcoin, and when you want to make a purchase is not the time to look for an exchange.
2: Acquiring validation for each transaction is a heck of a lot of work for individuals. It's not just pushing a button, it's asking and paying fees, and waiting an awful long time. Exchanges take up much of that slack by fronting the transaction for you.
3: Most bitcoin "investors" are not all that savvy - they likely don't understand the technology (or good old ledgers, for that matter), and don't want to.

Indeed. Which is why I think a deflationary system cannot work without progressive capital gain taxes, to make it easier for those at the bottom to save, and harder for those at the top to hoard.

It depends on how you define a stable society, I guess. In an utopic stable society, there might not be mortgages, but a strict earning-precedes-spending ethos. In which case living below your means and saving up is advantageous, as your money will increase in value as you wait for being able to afford a house.

No, that causes deflation, not inflation.
Inflation: Your money decreases in value, so there's little incentive to save but instead spend it quickly.
Deflation: Your money increases in value, so there's little incentive to invest money, only time and other resources.

In a growing economy, mild inflation is generally beneficial, but in a stable society, mild deflation cements the stability.

The real value of a penny isn't the face value, but as a lubricant for transactions.

Bartering using precious metals and official IOUs for them has worked fairly well throughout history.

This is incorrect. If you've had measles, your immune system is a lot more hardened than with vaccines. If you've been vaccinated, you need booster vaccines, but if you've had measles, you get a fever instantly if you get a vaccine, as your immune system goes into full attack mode. It won't just attack that one strain either, but anything that's close. The weaker "attack" of the disabled pathogens in a vaccine just triggers the immune system "enough" to protect you - not enough to put it in defcon 1.

The problem superbugs have in a "normal" environment without vaccines is that they're outcompeted by the less lethal strains. The milder versions of diseases will always win in the long run - killing your host is not a good strategy for bugs. Adding vaccines changes that, as you fight the strains that are prevalent, taking them away as competition for other strains.

(Forego still means precede, even though so many incorrectly use it when meaning forgo.)

I gladly advocate forgoing vaccinations for endemic and childhood diseases, because the vaccines are so effective. They reduce culling, and long term cause harm to humanity by saving individual children.
New harmful or detrimental mutations in the human genome that in themselves are not enough to kill someone, but in combination with diseases like measles have a statistically significant higher morbidity are allowed to spread undiluted into our gene pool. These saved children have children of their own, where they otherwise would have died. When some ignorant anti-vaxxer says that vaccines cause autism, they may very well be right, but for the wrong reasons. It's not the vaccine itself, but that children who might have died now live to reproduce. If children with autism have any lower survival rate if they catch measles than children without autism do, no matter how small that difference is, by vaccinating against measles, the prevalence of autism will increase. There's a significant correlation between vaccinations against childhood illlnesses and the next generation being sicker from other illnesses like autism, asthma and spectrum disorders.

And we get superbugs. Through vaccination against endemic diseases, we instigate an arms race, where new and worse strains appear, which we have little protection against, unlike the milder versions that outcompeted any bad ones because we didn't wage war on them.

For better and for worse, the reality these days is that most companies are migrating to cloud and devops, where you don't control your own computer, and don't have admins that understand the underlying architectures and the nitty gritty bits of how to configure a kernel or why.
Magic black boxes is the new standard, and control has become a negative word.

It doesn't end, and shouldn't. Every circumstance is different, and new problems can and will present themselves. This is why we have a legislature and government, instead of relying on black-and-white totalitarian laws and regulation, set in stone and not allowing adjustments to reality.

One of the functions of a modern government is to protect the minorities from a tyranny of the majority, and make sure that justice is kept blind, even if it means we sometimes have to deliberately blindfold her.

Depending on the application, it could be, yes. The difference in false positive rate between 90% and 80% is double.
If the recognition frequently leads to police action that can be harmful or disturbing for innocents, having a system that falsely identifies one group twice as much as another might cause tension. In that case, lowering the accuracy until it's equal across the board might be prudent, so black innocents aren't twice as likely[*] to be falsely targetted as white innocents are.
Catching more thieves might not offset that injustice.

[*]: Or even more, if sequential targeting occurs, trying the second on the list if the first fails, then the third. The total error rate accumulates faster the higher the uncertainty.

For typical small headphones used with phones, no, they're not "a few magnitudes higher in currents".
Line level is typically around +- 1.7V, and you can indeed drive some high impedance headphones from line out. (Not low impedance speakers, which if it doesn't short the output doesn't have nearly enough current to drive the elements.) Of course, that's not ideal, but it shows that it's in the same ballpark, not "a few magnitudes higher".

You were the one who brought up speaker cables and long runs. The 12 gauge or fatter speaker cables used there are a quite different animal to what you have dangling from earbuds, and not nearly as susceptible to interference. For the lightweight wire used for in-ear monitors, it's quite a different story. Heck, even adjusting the height of my desk causes hisses and scratches in my in-ear headphones, direct to my phone. But not when going through a headphone amp with a balanced output.

Um, that is what I said happens to a balanced connection.
Unlike an unbalanced connection where one wire is shared.

Speaker wires are a completely different beast, with enormously more power.