Was wondering how one could probably use https://github.com/FiloSottile/age or something.
(Not an emacs pro, so sure don't know some of the trivial ways to use this)
This is not true. There was a proposal near the start of the year. That proposal has been almost entirely ignored.
Would age provide any advantage over GnuPG to make it worth the bother to switch to a new message format?
Probably you would get better answers about Emacs on https://emacs.stackexchange.com/ or https://www.reddit.com/r/emacs/ .
EasyPG is very mature in Emacs, makes using GPG a breeze and is integrated really well. Age doesn't even support signing and has no Emacs integration.
I’m aware of the wiki article but that’s not any official position. In the very least anyone can edit that wiki.
Or just tick on the full disk encryption option in your OS (assuming it's a modern one like Win 10, recent Ubuntu, etc.). It's just as good at keeping your data protected at rest as any other encryption option you can run in userspace, and there's less chance of some file operation snafu accidentally unencrypting or leaking your data.
has tooling on pretty much every platform,
is a mature, well-established product.
The complicated features are optional.
Using something like age, with one reference implementation in Go, not supported by most languages, nor time-tested, is just asking for trouble, like surprise exploits or bitrot making your data unusable.
I am perplexed by the frequency of "PGP/GPG is old, let's replace it with something new and untested" posts on HN...
In software development, OLD is GOOD.
(As a side note, I don't think Debian has been at the forefront of rational decisionmaking for a while, so I wouldn't watch them too closely.)