And don't work. They were revealed to be useless way back when the Magic The Gathering Online Exchange crypto grifters pulled the first high profile scam, and they got hounded through all the "mixers" anyway. Chainalysis has been able to see straight through "crypto mixers" for almost a decade. (Yeah, there are probably way that right now you can't track bitcoin through other crypto currencies and back into bitcoin, maybe... But we are now a long long way from "good advice to an old guy who want to sell macOS utilities anonymously")