Android nowadays only ships with Gmail app. It can do generic IMAP but it's never been clear to me if the process is entirely on-device. I'd rather not keep Google in the loop.

That said there are some generic mail clients for Android. Not many are good, but they're out there. K-9 has recently received some love again.

There are several scenarios I can think of where it people would not be able to use IMAP or POP to get their mail, and you touched one of them: people without their own device.

There is also the matter of having to set it up, which is not accessible to many people who can't (or don't want to) handle the cognitive load required.

Two common scenarios are not knowing how to set it up, and not owning the device and thus not having the access to do it.

Two common scenarios are not knowing how to set it up, and not owning the device and thus not having the access to do it.