https://github.com/zachaysan/toolies/blob/master/wallet.dat....
That's my original wallet from 2011 that I uploaded to GitHub a couple years later when the amount of money it had in it became non-trivial. GPG works great[0]. I emptied the wallet near the top of the last Bitcoin run up, but honestly even if I still had money in there I wouldn't worry about commenting about how it's public.
As for the rest of it, he's right about metadata and right about human failures like following up with plaintext responses. But on the other hand if your email box leaks then at least most actors are not going to be able to break encrypted messages, which are arguably the most important.
[0] And yes I know the difference between symmetric / asymmetric encryption, but I'd trust it if I'd done it with keys too.