Well, that was just a simple example, I really want to exclude temporary torrent client downloads anywhere, such as *.!qB from qBittorrent and *.!ut from uTorrent. If only paths are accepted, then I guess I have to specify the download folder(s) as exclusions, but then that would also prevent scanning of the final renamed downloads (until I would move them, of course).
If not supporting simple wildcards really is a limitation, then I suppose the dialog should be fixed to not allow "invalid" entries, because I can add just *.!qB alone now, for example (hence my original question about wildcards, since the dialog does indeed accept that kind of entry; I just want to be sure it actually works because there's no official example in any documentation I can find).