They invest it one of dozens of other regulated ways. For example: Stock market, housing, financial derivatives, etc.
Also: A crypto stablecoin is (supposed to be) pegged to a major currency, usually the USD. So in terms of return, it shouldn't matter if you have your money invested in stablecoin or cash under your mattress. Oh wait, it does matter, because most stablecoins are scams and you'll eventually lose all your money.
Also: A crypto stablecoin is (supposed to be) pegged to a major currency, usually the USD. So in terms of return, it shouldn't matter if you have your money invested in stablecoin or cash under your mattress. Oh wait, it does matter, because most stablecoins are scams and you'll eventually lose all your money.