It is one of my amusements to write my own email software, so perhaps I haven’t given mail_daemon the full desperation chance it takes, but …
It’s about time to do some cleanup on my remote email account, since it’s getting pretty near 10,000 stored messages. (I like to allow only 4 columns for the message index, so …) When I tried to point mail_daemon at that, it could not succeed. Running in the background as it does, it wasn’t really able to communicate with me in any useful detail about the problem.
Back when I was working in this area, the IMAP guy was sort of enthusiastic about the idea of an IMAP filesystem, which is somewhat like what we have here. He’s gone, though, and I’m here, and I personally prefer to start up a connection in my own user space when I need to look at my email, just like data from everywhere else. I get what I want to get, when I want to get it.