I’ve been using GnuPG for about 15 years now, on and off. In all that time I’ve encrypted maybe 100 emails. They’ve mostly been mails sent to test out my GnuPG/MUA integration, or send snarky comments to the other people on my crypto course at uni. I don’t even want to encrypt my mail: it’s annoying.
However, I sure have encrypted a lot of files with it for work over the years, and I sign all my outgoing mail. GnuPG/OpenPGP isn’t the answer for ubiquitous encrypted communication, but it’s still extremely useful for other things.
I sure hope this is a back story of sorts for something he’s working on to make email secure by default, but I’m going to guess not. The email ecosystem is a nightmare, and unless he’s working for Google to bring it to Gmail, and for yahoo, and outlook email by default, it’s unlikely to gain the wide stream attention that it’d need to be relevant.