I think many people see crypto currencies, until they are regulated, somehow, as legal ways to not pay tax. Obviously they are not and when the gov catches up, they might get you anyway. They are very patient.

Ofcourse things are easier to hide if you want to for a while, but how would you turn it into actual money if we are talking large amounts?

I think "outlaw" upthread means "take notice of the particular mechanism, and sufficient steps to make it untenable for most use".