It's not even that. The two main problems are that Bitcoin in non fungible - that is 1 BTC != 1 BTC, and that comes from the second problem - BTC isn't anonymou

It's not even that. The two main problems are that Bitcoin in non fungible - that is 1 BTC != 1 BTC, and that comes from the second problem - BTC isn't anonymous, in the sense that all transactions are publicly available and there are tools already that give great deal of deanonymisation capabilities. Now if you use a tumbler to get "fresh" coins, it may be that some of the source coins were involved in hacks or drug deals and are blacklisted. This means when you'll try to withdraw you likely get them confiscated and get yourself in trouble.