What I'm reacting to is your inability to quantify your opinions. Specifically, 'disturbingly large percentages' and 'rather large percentages'.
> it's the cryptocurrency world that is presenting the new thing, so it's on them to prove that what they're offering is an adequate substitution for what we currently have.
"for what we currently have". See, that's the thing, we had newspapers and tv before we had the internet. The internet came along and gave us an entirely new medium. It took a while for people to get used to that. You're in that phase now.
While millions of other people are off experimenting with these new things (and effectively using as part of their daily lives). Nobody forced anyone to use the internet. People gravitated to it because they found value in it.
Just because you have come to the opinion that it has 'large percentages' of grift, doesn't make that opinion true.
In any case, since you brought up burden of proof, it's the cryptocurrency world that is presenting the new thing, so it's on them to prove that what they're offering is an adequate substitution for what we currently have. I am the potential customer that has to be assured about it. So, in the larger sense the burden of proof is on the cryptocurrency people.