What you actually use aliases for

Specific situations where giving out a throwaway email beats giving out your real one.

Use case
Newsletter signups
If you sign up to one. Get something free. And then they sell your address. You get to murder the alias and the spam stops. Forever.
Use case
Free trials
Sign up. Try the thing. Cancel. Kill the alias. They can't email you. They can't text you. They can't 'we miss you' you. Done.
Use case
Dating apps
Sign up. Match. Decide. If the app starts spamming you, or it gets bought by a company you don't trust, or you just want out — kill the alias. They lose you. You stay anonymous.
Use case
Crypto exchanges
Sign up. Trade. When the exchange inevitably leaks the customer list, the phishers don't get your real email — they get a dead alias. You don't end up on every 'urgent: verify your wallet' scam list in existence.