You've intentionally reduced PGP to your narrow use case. PGP/GPG will also sign and not just encrypt. If you're going to debate the subject do so honestly.
Yes, that's my point. PGP/GPG's ability to sign things is an "also", but it's the only thing it's good at. Build a version of GPG that only does signing and verification, and nobody will be tempted to use it for privacy.