Sometimes you don't want to have large quantities in cash. So you store it in a bank. But sometimes you want it outside of the (possibly corrupted) legal system

Sometimes you don't want to have large quantities in cash. So you store it in a bank. But sometimes you want it outside of the (possibly corrupted) legal system, or want to take money outside of the (corrupted) country. In that case, a stable cryptocurrency seems to do fine. It's truly online without any government being able to confiscate it (if you play it smart). It all depends on the use-case.