I really don't see your point here. I'm agreeing that you can't use it for everything. But what's wrong with that? There are plenty of things in this world that aren't useful in every circumstance and yet that doesn't mean those things are worthless. Use them for the things that they're good for. Elsewhere in this thread I listed off a whole bunch of non-stock, non-currency applications that have been built on blockchains if you really don't like the monetary applications.
As a side note, though, I'm kind of amused and baffled that the Grand Nagus of all people is dismissing any monetary uses for cryptocurrency.