BTC and many cryptos will collapse, because the dollar and the euro are worthless, as the these fiat currencies down spiral to oblivions, many will rush to withdraw and convert their token to fiat to then either buy something tangible or to shift to other speculative investments strategies, that's for the smart guys that can even afford to lose it all without undermining their comfortable standard of living.

All the other schmucks will be wiped out, go bankrupt just when a global inflationary depression hits the whole global economy.

Cryptos are mostly tied to fiat, if suddenly fiat hyperinflate to become actually worthless, or if cryptos are made unconvertible to any fiat, the Ponzi crypto gambling scam would collapse overnight, leaving behind all the dumbed down brainwashed purist cointards holders and the stuck wannabe rich quick bagholders.

Not even mentioning the social meltdown as a result of many clueless idiots that would have lost third parties savings, that believed in their claims about paying them back double digits percentage return over their investment.