Auto-playlists can be set to be automatically exported.
But (far as I know) this will only occur when shutting down MusicBee.
So when you leave MusicBee open for a long period of time (perhaps days), these auto-playlists will not get updated.
This is a request for an additional option for automatically exporting an auto-playlist (and a slightly better description):
☑ automatically export a static copy when closing MusicBee
☐ and at an interval of ... minutes