reads from Maildir, writes to mbox

$ mail
read a message, then
? q
Saved 1 message in /home/jidanni/mbox
Held 5 messages in /home/jidanni/Maildir/

Proof that the above is bad:
The next time the user does
$ mail
he will only see four messages.

What other mail program ever made the user's read messages "disappear"
somewhere else, so when he restarts the program he can't find them anymore?

Why can't read messages be saved in the same place they came from, like
mutt?

If mailutils is smart enough to detect
MAIL=/home/jidanni/Maildir/
for reading, then it should also use it for writing, by default.

Just put them in /cur not /new.

And (info "(mailutils) mailbox statement") doesn't mention how to fix it.

Maybe there should be a variable,
"use_the_same_place_to_store_read_messages", on by default.

Version 3.5.