You could ban companies from interacting with crypto currencies, which would kill off the entire ecosystem, and make them unusable for the majority of people and purposes.
I addressed this in my OP. It would kill off the legal ecosystem that earn them tax revenue but would have little effect on the illegal ecosystem they intend to stop.
What stops somebody from interacting with a foreign company that exchanges crypto and $LOCAL currency?
Sure, the entire ecosystem would take a hit, but also note that many US companies have actually bought Crypto, people recently bought crypto on margin, and, those who still own crypto, can exchange it outside $COUNTRY, and convert currencies.
