[bscphil]

One of the many advantages of using a hosted solution with your own domain is that you can receive email from arbitrary addresses in the same inbox. For example [e-mail] gets sent to my inbox at Fastmail. [e-mail] doesn't exist, so there's no way to get my "real" email address from what I give out to merchants. If I start getting spam on an address, whoops, you and everyone you sold my email to get sent to a black hole in the cloud.

[JustSomeNobody]

This is called subdomain addressing or subdomain stripping in case anyone wants to look up how to do this with your hosting provider.