The tool is just pulling one encryption key from your local GPG keyring. What's to maintain?
I promise this happens all the time to people for lots of stupid reasons.
Use keyid instead.
> What happens when your key expires?
GPG will refuse to use it for encryption. Create a new encryption key.
> What happens when the output format changes?
N/A here (?)
> What happens when the key expires and it's attached to a hardware device?
You got me.
If you have an expired GPG private key it will still decrypt things encrypted with the public key.
Non of this is impossible to overcome. Yet, I still was sometimes relied on to debug things.
(admittedly AFAIK encryption is handled by key expiry poorly overall in GPG - the lack of perfect forward secrecy means an expired key which leaks can still decrypt all the old messages if they were intercepted).