As long as you can lose every bitcoin you just because your flash drive malfunctioned it will never catch on. Besides, it's more worth it to kill the "stores" (Such as silkroad) that accept bitcoin that to stop the users from using Bitcoin itself.
Really? You don't understand digital currencies then. The point of them is that they are supposed to be like cash. If you lost your wallet with cash in it, sorry, that cash is gone forever. That is what makes them so useful. What you CAN do with digital currency is make a few backups in case your computer crashes, or as you say, you lose your flashdrive. When you actually want to spend some, you just transfer the amount you want to spend. Kind of like a real wallet, where you don't withdraw and walk around with all the cash of your entire bank account, but maybe a couple hundred bucks for a night out.
The best thing of it all is it is really really really easy to do, nearly instant, and no middle man fees.
I think the disconnect with digital currency now is people are so used to trusting banks to hold their money, which is FDIC insured. Digital currencies do not have that same type of security. But they also don't have to deal with banks. Furthermore, digital currencies are there largely to exist free of governments and regulations, relying purely on the natural market of supply and demand. It is a philosophy that might not be all that crazy. Remember when Greece this past year was about to collapse? Guess what happened when the people there tried to go to a bank to get their money... the Greek government said "Nope!" and shut all the banks down... At the end of the day, countries like Germany, richer countries bailed them out.
What will happen if a day comes where America's debt problems get the best of us? There is no one to bail America out. A lot of people don't think it's possible, but it's possible.
Even if none of that ever happened though, digital currencies are amazing, and they are not going anywhere and will only get easier to use. Look at the recent successes of Dogecoin... my mother, probably the most computer illiterate person that I know asked me the other day about how to get coins. Seriously... It might take 2 years, it make take 10, but it's gonna happen...