Good luck safely store your money being Russian or Iranian (or other citizen of any fascist regime who is considered not a human by both his own country and westerns). Not a legitimate case, I suppose.
I use bitcoin to buy things all the time. Full stop. I've made a bunch of money from that investment too. Full stop. Having a currency that is not bound to a state can very possibly be a good thing. Full stop. Scams exist in many industries and in crypto it is rampant due to its lax regulations but that doesn't mean the industry is a scam by definition. Full stop.
There are many avenues to transact moneys. Crypto is one of them. It has a handful of really good use cases. I agree that there are often (usually?) better ways, but cryptographic blockchains that house value to the tune of billions of USD and never goes down or breaks is quite powerful and should be respected as such rather than being seen as purely inferior.
There is no legitimate real world use case for all of this. Full stop.