I agree it makes sense messages don’t vanish silently; but there also was no any indication whether message was delivered or not (because of misconfigured smtp/no connection). I wish there was indication of “no special directories assigned” state as a safeguard for noobs.
Also, for some reason I observe doubles of each “special” directory — i.e. two “sent” dirs, two “drafts” and so on. One copy was always empty and the other one was synchronized with corresponding directory on my mail server. Custom directorier are not duplicated. My mail server does not contain empty directories, so I thought the empty copies were specific to k9-mail. But they seem to be useless and I have no idea how to delete them.
I’ve assigned the “special” roles to non-empty instances (which are in sync with the server, so it makes sense).