Because resize-mini-windows may be nil. And the message may be invisible.
When emacs displays combination of the prompt and the message, if user input something, doesn’t the message disappears?
This is what the current code does,
The current code doesn’t display the message transiently. It displays it forever. User needs to press a key to restore to the prompt. Is this a bug?
and the problem with that is that
some uses of 'message' don't expect the message to stay for 2 seconds,
and some expect it to stay forever. This information is not explicit
in the call to 'message', so there's no way of communicating in down
to minibuffer-message.
Do you mean the scene “Foo…” followed by “Foo…done”?
I don’t think this is a problem. These are just status which are not important. And they disappears quickly when user is busy editing. And the really important ones may put an indicator on the mode-line.