Cool, I agree no one should use PGP servers the way I described, but you never know what people are doing out there. To do things the proper way, as you described, is difficult in practice for lots of people.

To answer the question, the point isn't to get an (email address, GPG-key) mapping. It's to get a (public-internet-identity, GPG-key) mapping. People sometimes do this today in an adhoc manner (e.g. tweeting your GPG fingerprint). We want it to be checkable by user-friendly software.