The same could be said for a server that has say an out-of-band management feature (ILO, BMC etc.) and then the OS layer has a separate IP. We can already add new usernames and passwords with customizable names so this would be a great complement.

This is super useful for managing credential for sites on different development environments (dev/staging/prod). And for sites just being available under different URLs.

P.S. Just to make it clear - browser extensions should also use this feature to make it really useful.