Some crypto are centralized, some are decentralized. Some are inflationary, some are deflationary. There is also a big difference between holding your crypto in an exchange (where they control the keys), and holding them in your own wallet with control over your own public/private keys (not your keys, not your crypto).

Crypto can be good, but like any "money", they can also be bad depending on how they are structured. Research before you buy into any crypto.

Ideally, the best ones, are ones where you have control over your keys, are not held on an exchange, and are mostly deflationary (or only slightly inflationary in a controlled known manner).