In my experience of recent years, addresses like abuse@, webmaster@, hostmaster@ and postmaster@ normally bounce. It’s a real nuisance when I want to report bugs in web systems, or in email systems where they’re doing enough things badly wrong that they trip (or get close to tripping) spam filters, et cetera.
Sadly I never setup any of those, usually only admin@ and then move on. To be fair I usually list one of the available emails on my sites where it makes sense, or provide some way of contacting me directly. I will definitely create those and forward them to admin@ from now on though. But the issue still remains as others said, now you can claim you never got an email.
