If the use case is tax avoidance, bribes, theft, scams, money laundering, funding terrorism, evading sanctions, ransomware payments, extortion, illegal purchases then crypto is immensely successful.
not to be whatabout... but... anything of value is used for all that too, in much larger amounts.
it is wild to me that people expect that crypto is supposed to solve a problem that is as old as currency.
these use cases exist with all forms of cash too