The trouble with crypto is how little one can actually buy in tangible goods and services with it. It's shit at being an actual currency right now. The public nature of it also means that it's like posting your credit card statement in the town square.

As a store of value, it's a risk. Risks are manageable when understood though. BTC has the 51% issue where China collectively owns the network already and could make unilateral alterations to the blockchain ledger, but even apart from that, the highly unstable valuation makes it like buying a single high risk stock. Most (but not all) altcoins derive value from BTC. If you have spare cash and can hodl your crypto for a long time before needing it again as regular cash, it could work out great. Have multiple coin types and accounts at multiple exchanges in case there's a big selloff and logjam (think like the great depression bank run), but keep your own coin in your own wallets as there is already a rich history of exchanges "losing" their users wallets where they kept sole ownership of them.

As a Ponzi scheme, it's stellar. Easy to get in, easy to partially divest to hedge your bet, and barring the 51% issue, there is likely to be a good period of warning time to get out and not be the one left hodling the bag. To be clear, cryptocurrency is not actually a Ponzi scheme, but since it's solely backed by confidence with zero hard assets or threat of force, it needs to be treated as such.