The trouble with POP is that it is designed to let you MOVE messages from the email server to the device you read them on which is fine back when you only read your email on one device, but would now mean you have some mails on one device, some on another etc etc
Obviously there are ways round this but they are all basically bodge tape.
IMAP is more like what we expect these days: the email stays in the mail server and you just view them with whatever device is handy (webmail, phone, desktop mail client). You always see the same messages and any changes you make (deleting, replying etc) can be seen on all the devices.