He didn't make gold illegal, gold still has value as a precious metal and trades as a commodity - he just moved to end gold's use as currency and associated banking and transactional activities that had to do with transitioning from the gold standard. I think those dynamics were largely peculiar to the move away from the gold standard and not a terribly persuasive analog to the possible federal interest in regulating bitcoin.
Bitcoin's perceived value comes from its asset value based largely on its programmed limit past which new bitcoin cannot be created, not so much in its transactional value as currency. Yes, if the US prohibited the transacting of any business in the United States with bitcoin, it would harm its value but less than half of bitcoin trading in 2020 occurred on US exchanges. The US can't outlaw bitcoin worldwide and I'm not really sure why it would ever want to try absent a truly monumental change in how business is conducted in the US. Asset trading and some novelty consumer use as a currency don't seem to raise any of those concerns.