Forget the bitcoins, why would you throw away a perfectly good, supposedly working, hard drive? That's a shame. And before secure formatting it?
Probably scrap it for the magnets at some point. Those are much better than the fridge magnets you find at the store!
A 128GB flash drive costs around 5 times as much as that enclosure. Yes, it's better, but it's quite more expensive. A more comparably priced 32GB flash drive stores several times less data (which might matter to you) and may have write speed that can't even saturate USB2 (ditto; I installed Fedora on a 16GB flash drive that has max 3MB/s write speed and it takes amusingly long to install updates, though its read speed is decent and doesn't suffer seek time).
Flash drives will get cheaper, but the meaning of "5 years ago" will change just as quickly (given current trends).
I have the USB 3.0 and thunderbolt adapters for the USM cases. Manufacturers should really switch to this format.
Even if the HD was ok, they won't even bother opening it up.