You're right about having to be able to spend the cryptocurrency for anything to move further. The problem is we're not quite in the spot yet. I'd love to be able to take most of my pay check and dump it into bitcoin (or something else) and live off that more than living off fiat. The problem right now is, I have to turn it back into fiat to spend it. Combine that with all the fees of buying bitcoin, transferring, trading, transferring back, and exchanging back to fiat, it's really not practical yet. But, it's coming. It's just a matter of time before somebody gets a debit/credit card past the gatekeepers like Visa and MasterCard to be able to spend the cryptocurrency during day to day transactions.

At the speed this technology is moving now, it won't be too much longer. Just thinking back to when debit cards were just coming out. It took quite a number of years for it to be used more often than cash. Cryptocurrency will most likely happen faster because the infrastructure is already there, though.