The line is that you don’t criticise tankies/hexbear on lemmy.ml. They don’t take kindly to that sort of thing.
It can have legitimate utility, for example I want to exchange money for international services without a credit card or mailing an envelope of cash/cheque.
It does it infinitely more inefficient, slower and insecure than all other existing alternatives that can do this (and there are a lot of alternatives which doesn’t involve blockchain). Which is also why people doesn’t use it for this.
Their posting history reveals them to be a racist troll.