No, no it certainly would-fucking-not.
Fortunately for the rest of the world it's illegal for the same reason google isn't allowed to pay your salary in google bux, and facebook isn't allowed to pay your salary in facebux.
Good thing there's stuff like laws people much smarter than you happened to enact before you were born so you didn't grow up one day and soil yourselves while they retired.
Cryptocurrency isn't going to the masses. It's going to broke AF basement dwelling creeps who don't realize that there's still a world going on outside of the internet, where most of the people are.
There are more than 3 billion people on the internet. The main reason the other 4 billion people aren't on the internet is poverty. While there will always be a world outside of the internet, you'll be kidding yourself if you think that brick and mortar stores are going to outcompete the likes of Amazon.com and other ecommerce platforms.
https://www.youtube.com/watch?v=6MnQJFEVY7sI don't think that these 4 billion people living in poverty are there because amazon didn't give them a good deal on shea butter and charcoal filters, and that they have no way to settle their debts without an ecommerce platform.
They need what the rest of the world has right now - a fully funded debt fueled top down controlled government structure that isn't constantly being destabilized with the full force of a military that is actually strong enough to decimate public uprisings. Or the technology to cause them from not happening to begin with.
Not some seeds, dreams and a belly rub. Not moon rockets.
No it won't be brick and mortar, but composites printed from the front of the welfare line that gets them in order. And it won't be blockchain technology they pay in, because they won't have any need for money. Commerce will be something that gets phased out anyways, and as you've already pointed out, doesn't even currently exist for over half the people on the planet.
Can't need what you never lost to begin with, right?