I get the impression that the article's author didn't really read the linked help page. It's basic auth that's getting deprecated, due to being considered a legacy authentication protocol. For good reasons, as described. That aside, POP should really be considered legacy, it comes with many downsides that hinder people's e-mail usage. IMAP is definitely more functional, but has a successor - JMAP. So in some sense, i…
What downsides POP3 has? Looks like a terribly simple protocol and does the job of moving messages from one place to another quite well for me. Having to use anything more complex would be a downgrade. More complex to setup on server and client side, with more options and more problems to take care of. I like to use the simplest tool for the job.
The workload required to poll is heavy. You need to reconnect TCP, TLS and login. Once you find you have no messages, you have start over to check again. https://billpg.com/pop3-commit-refresh/
Clients and servers need to keep a short-term "message id" to long-term "unique-id" map. https://billpg.com/pop3-message-ids/
Deletes are batched and only committed at the end of a connection. Unless you're willing to close and reopen a connection right away, any messages you delete are in a not-quite-deleted limbo until you close the connection. https://billpg.com/pop3-deli/