Fastmail has this nice "masked email" service for random-generated alternate emails you can use. 1Password integrates with it to make it seamless to generate a masked email during sign-up.
Besides privacy, these are so helpful when quitting a service that doesn't offer self-service account deletion. You can start blocking emails from this address or delete the email address completely. While some of your data will still be there, at least you can stop getting email from them.