Exactly this. Burner emails can still be read if the user needs to reset their password. It just makes it easier for the user to make sure their email doesn’t get abused, sold, lost by the site’s owner.
I will only use my real email on sites that are relatively well known and that provide services that I want to get updates for, or that provide some team/social usage and I expect people to try to find me by it.
I have a couple of domains with catch all emails that I use to sidestep the blocking the op is attempting. I have the emails stored in 1Password and generate new ones for every site the same way I do passwords. It is very often than some of these one-off emails will start receiving spam or being contacted for different reasons than where the email was originally used in.
Too many people have betrayed trust. This is why we can't have nice things.