Yup. Building a email-plugin that uses Keybase for key-discovery has been on my ideas list for years now, but I never got around to it. Maybe someone else will.

https://github.com/captn3m0/ideas#email-on-top-of-keybase

They did recently add a "Crypto" tab, but it's totally opaque to me as a user as to how it works and why I would use it (aren't my messages within Keybase already signed and encrypted? should I be concerned they aren't?).

I agree that they probably should just lean into PGP as at least it would make sense for folks who know what it is.

Agreed. I was disappointed that they instead decided on a failed attempt to capitalize on a cryptocurrency via airdrops (ironically they attempted this a couple years after the hype)