That depends on why you do it I'd say. Is it obvious for a human (or an LLM I guess) whether two aliases belong to the same person? Sure. But you can still separate which service an email you received belongs to, ie who leaked your data, or got breached, who sends you spam, etc.

not if you can use a catch-all for you domain. Then you can still do per-service aliases and filter them all accordingly.

If you use Addy you can do both. Use your own domain for accounts you have (businesses you deal with) and then when you need more anonymity or a throw away use one of the standard domains.

I think, maybe I am wrong, but you can use your own domain for email aliases. So the usecase of every site has different mail remains.