It's future proof for several reasons:
--A cloud service(I'll use Google Drive as an example, but there are many) is distributed, with backups, and will shift data over to new technology as needed. Pretend Google Drive started off 30 years ago. At the time, they'd probably store your data on tape(yeah, yeah, slow access times, but that's not the point of this example). Then they switch over to ide hard drives. Then they make the switch to scsi, then sata. 5 years from now they switch to SuperDuperSSD. From your perspective, none of that matters. From your perspective, you put data on Google Drive, you take data off Google Drive. The technology they store it on doesn't matter and is going to change and adapt as new tech comes on line. I put my money in the bank, I take my money out of the bank. I don't care what the bank does or how they store it, I just want my money.
--A cloud service is redundant. When Lex Luthor finally causes that earthquake and makes California slide into the Pacific, your data is still safe on one of the other server centers that Google has, just for that emergency.
--A cloud service is stable. A major cloud service like Google Drive is not going to disappear overnight. Unless something causes the government to seize all of their servers at once, with no warning, and in a way that would never let you get your data back. That is highly unlikely as of today. So even if Google goes bankrupt, you will be able to see it coming and get your data back from them before the cut off date. Besides, you said this is a backup of a backup. So your original storage place is destroyed, your off-site backup is destroyed, and Google is destroyed utterly with no backups and no way to access that data. All three of those things have to happen at the same time. If all three of those happen on the same day, you will have more to worry about because someone probably dropped the big bombs.
--Someone else takes care of operating the server room. In another response, you wrote: "if I put it on a server now, I have to keep that server going for the next 10 or 20 years." With a cloud based service, that isn't an issue. I don't know why any person(not company) today would bother putting up their own server, except as a hobbyist's exercise. Or unless you are insanely paranoid.
--Access from anywhere. Seriously, if your first two backups are gone and the entire internet is down for more than a day and you need the data immediately, either one or two things will happen. Either people will understand that something very bad happened and they will make allowances for that knowing that you can get the data when the internet is backup. Or they've dropped the bombs and your main concern is radiation poisoning and the hordes of mutant zombies.
--A cloud service has zero to no cost. You get gigabytes of data for free and you said this is under a meg.
Seriously, as a backup to a backup, you have really over thought this. Now if you want to do something as a cool thing to do, that's fine and good and proper. Pick the QR codes or whatever strikes your fancy. But if your concern is availability and future proofing, just stick it on a backup service. Doesn't have to be google. There are four or five top tier online storage companies that aren't going anywhere in the immediate future. And if you happen to pick the wrong horse, just download the file before they go under and pick a different one. Microsoft's live drive actually meets the FERPA standard for data security if that's a concern, but you said it wasn't.