(On the other hand, if large companies will accept it in payment, they've probably got an idea that a given currency will be around next month or next year.)
I don't think this is the most likely answer. Most likely is that the big companies have an instant exchange set up where a purchase made in bitcoins is immediately converted to dollars, and they charge their customers a small transaction fee in the form of an exchange rate difference.
...Someone from the back row shouts out "Because our AdSense profile has determined you were visiting websites about cigarettes recently, your health insurance premium has gone up by 5% and you will probably die slightly sooner. Remember, [i]f you have something that you don't want anyone to know, maybe you shouldn't be doing it in the first place!"
Is it cynicism if you're just using a Markov chain to predict what other Slashdotters will say?
(Although obviously this is auto insurance, so I'm sure someone can translate the threat appropriately.)
I will also tell you that from 3 decades of watching this stuff I believe that you've put yourself at the mercy of the propaganda people. They are the ones who retain, manipulate, and present the information that you are election-night-cramming on. Off the top of my head I can think of a dozen examples of candidate-selection-altering events that, when I go back later to see what history has had to say, are entirely missed, glossed over, or are otherwise mischaracterized.
In summation (not to the parent at this point) - get yourself to a town hall meeting or two sometime, and get off your lazy butt and walk to the post office or a polling place.
Your argument that "it simply takes too much time to do the research" reads to me as an admission of being uninformed. Your statements preceding that set off every alarm in my system for propaganda abuse.
Do your own research. If you care about an issue watch your local, state, and national politicians over time and keep track of what they DO, not just what they SAY.
It's not a given that low voter turnout is a problem. We don't need more low-information voters (89% agree that DHMO should be banned) and we don't need to coerce those who do not vote to signal their non-consent to the system.