While you're right, I'd recommend against both for the specific use-case. You just added another layer. The extra software needs to be available, maybe it's not developed anymore and won't compile on your system, maybe they changed the alphabet from which the words are generated, ...
OpenSSH private keys are armoured by default, gpg-keys can be exported and imported in an armored format - and everything else can be just printed as hex representation with whatever tool (e.g. `od -Ax <file>` or any other).
z-base-32 isn't going to magically disappear off the face of the earth. Anyway, here's a 32-byte secret key as hex. Still easier to type in than to drive to a data center. GPG is just horribly verbose, and the old school RSA keys are huge in comparison.
It's a 50-line CLI I wrote (just like `entropy` on the other line). It's just a simple interface for https://gitlab.com/NebulousLabs/entropy-mnemonics which is one of the many different "encode binary as words" things out there. It's the idea that matters more.