Unfortunately though, all those good things about cryptocurrency depend on it being as easy to trade as fiat currency. That wasn't true five or six years ago, but then that could be excused because it was a new technology. But, it's still not true and that's why I'm getting more skeptical as time goes by.
It isn't true for several reasons. The biggest is that value fluctuates too wildly and is highly unpredictable, so it works best as a currency if suppliers constantly change their prices and you convert your cryptocurrency to fiat as quickly as possible. But if you do quick crypto-fiat conversions, you often run into either slow transaction times or transaction fees many times higher than the most expensive payment processors.
(I genuinely hope that I'm wrong and feel like a Luddite when I read this in five years.)
> That you can't predict the price is totally irrelevant...
For something that aspires to be "money", that is highly relevant.