Re: own domain and use a unique LHS
I'm not too convinced about that. If you already reuse your email address, chances are you will reuse your username too. If you use a password manager to create unique passwords, you are already safe from credential stuffing attacks, a unique username will offer you little extra protection. Finally, the website will still store your email address as a way of contacting you, and in case of data breach it's certainly both your username and email address that will get pwned.