If we start with the definition of centralization.

The key word here is 'authority' which literally means "who gets to decide". Decentralization is meant to solve the problem of who gets to decide because whoever decides has power over other people.

Are there other use cases for decentralization? Maybe. But we shouldn't forget what problem decentralization actually solves.

I agree we don't need to decentralize everything and most of so called 'decentralized' crypto isn't even solving for the 'authority' problem. In many cases, it's actually worse.