I can see it making sense if you're already using the mail servers of the company that made the app (gmail for example) since they already have unrestricted access to your login info and mailbox anyway.
I guess otherwise I'd rather it be my phone regularly polling my mail server over my connection than a third party regularly polling it using theirs. I can see it being a popular option for folks on expensive/very limited data plans though. It doesn't take a ton of bandwidth to poll a mail server, but checking every 5-10 minutes it could add up.
iOS does that, maybe, but Android doesn’t. The mail client I use on my Android phone notifies me in a timely fashion when new mail arrives, often in less than a second. It just uses IMAP’s IDLE command to wait for new mail. If the connection drops it can just open a new one.
Does it occur to you that there are so many different variants of Android and they all do their own thing regarding background processes? It is so complicated that you can find websites like this https://dontkillmyapp.com/
That’s a fair point; I hadn’t realized how bad certain brands could be. The last Samsung phone I owned was from about 10 years ago, and it worked just fine. I replaced it with a Google Pixel last year when the 3G networks started getting shut down, and it works great too.
I guess otherwise I'd rather it be my phone regularly polling my mail server over my connection than a third party regularly polling it using theirs. I can see it being a popular option for folks on expensive/very limited data plans though. It doesn't take a ton of bandwidth to poll a mail server, but checking every 5-10 minutes it could add up.