"works great" as in... how? it's all way too slow and volitile and cumbersome to handle the global financial system, so nobody actually uses it as currency. in what sense does it "work great?" in theory it works great, but in practice, not so much. nobody wants to pay their rent with bitcoin if the price has shifted down 20% by the time it gets processed.
in practice it's also really easy to link your crypto transfers to you. it only takes one opsec failure and you're not anonymous anymore. so i really don't think it works "great."