Currencies are the only non-scam use-cases of crypto. However, the problem is that cryptocurrencies make trade-offs to be able to operate in a hostile environment. If you don't operate in a hostile environment (let's say your business has no reason of being shut down by neither the mainstream payment processors nor governments) then you're better off using established, trust-based payment methods which are more efficient because they don't have to operate within the threat model that cryptocurrencies operate in.
Crypto is trust-based, vastly more than government-backed fiat
The value of a coin, and the whole crypto system, is easily manipulated by the few-% who own most of those coins -- and likewise, by the two-or-three mining companies who mine the vast vast majority of them
"trust" in the crypto sense is a bizarre mathematical term, which has no relationship to trust in the fiat sense.. in that sense, crypto is a more extreme version of fiat -- there is nothing backing it, no gov, etc. other than the faith of its users
