Good thing I already jumped ship lol

IIRC, POP3 downloaded all emails to local device. If you have more than one device, the first one gets it all and the second or more see nothing.

IMAP kept the messages on the server so there was one source of truth and multiple devices could access the same emails.

Most email clients support both. There are probably some people still running old POP3 clients, or they set it up one way and never bothered to change.

Not sure why gmail would care. Code's been working for decades. Unless there are security considerations not worth mitigating.

They wake up every day and try to decide how to lose users. From killing things to enshittifying them.

Good, nothing of value is lost.

Then how will the Vatican get their mail?

To be clear, this is about using POP3 to pull other accounts into Gmail, not using POP3 to fetch from Gmail.