It’s amazing how little the general public know about crypto currency. It’s no Ponzi scheme, its quite straightforward, the coins are hard to find as you to mine (hash) for them and this makes them rare just like how finding gold when you dig is rare. They use a blockchain to ensure people don’t just create digital copies and to ensure unique coins.
Put it this way, if your government decided to start printing money and say distributing it via stimulus checks, this will cause inflation and devalue the entire currency. This can be extreme (look up the German weimar republic that witnessed comic levels of inflation after the great war). But this can’t happen with crypto currency. It’s immune to manipulation from governments and bankers. It won’t go away, in theory it should stand the test of time. Well, unless someone develops a super computer capable of hashing fast enough to find all the coins. But this is barely in the realm of possibility at this point. Quantum computing perhaps. But even then steps can be taken to ensure the coins are still difficult to mine.
I’ve made a fair amount of money trading crypto at this point but it wasn’t easy and I know people who have lost (mostly amateur miners). It’s very volatile at the moment but over time things will settle down.