We need a keyring at a company. Because there's no other media for communicating, where you reach management and technical people in companies as well.

And we have massive issues due to the fact that the ongoing-decrying of "shut everything off" and the following non-improvement-without-an-alternative because we have to talk with people of other organizations (and every organization runs their own mailserver) and the only really common way of communication is Mail.

And when everyone has a GPG Key, you get.. what? an keyring.

You could say, we do not need gpg, because we control the mailserver, but what if a mailserver is compromised and the mails are still in mailboxes?

the public keys are not that public, only known to the contenders, still, it's an issue and we have a keyring