allegations of bitcoin being used for untraceable money laundering

You can not easily ship large amount of currency between countries. That's also why "laundromat" banks are now mostly extinct.

With Bitcoin trans-border transactions are easy. You can have a "washing machine" exchange in Peru that is doing laundry for gangsters in Croatia buying drugs from Afghanistan. With pretty much zero chances for the law enforcement to track monetary flows, as you don't need anything but a server to set up a new exchange.

Heck, there are even "exchange goes out of business" sureties that use Etherum now.