I can't help but think cryptocurrency is a lot like the Tanzanian money the crew was paid with on one of our high-speed ferries that was operating for a few months between Dar Es Salaam and Zanzibar. Grocery bags full of money that they could not convert to dollars or any other useful currency and were not allowed to take out of the country. They spent it in country on a grand safari adventure and then high-tailed it out of the country soon afterwards.
If you are an American, you must pay your taxes in USD. So even if every other possible use of the money was replaced with tulips, you would still need to have some USD so it would still have value.