Never said illegal stuff will disappear don't strawman me. I stated a historical fact that the government ban on alcohol deterred about half the population from using alcohol. It would be safe to assume that the government banning bitcoin or any shitcoin would deter people from using it. How many? I don't know.
Regarding the shitcoin monero:
https://crypto.news/monero-privacy-bug-decreased-anonymity-for-3-years/
https://cointelegraph.com/news/newly-found-monero-bug-may-impact-transaction-privacy-developers-warn
https://decrypt.co/76938/monero-developers-disclose-significant-bug-privacy-algorithm
The major "benefit" that people shill monero for is its privacy which clearly is flawed. The reason why bitcoin is simply better is because the network is more secure and the supply is actually scarce. Monero has no fixed supply and it's difficult to run your own node. If monero ever got big enough, it would be easy for government to just take control of it since its blockchain would grow so large ordinary people can't afford to run a node.