1- You've posted the same info in Bug Reports and in the Wishlist. It can't be both. If it's a verifiable bug, it will probably be fixed. If it's a wishlist request, it's up to Steven whether to implement or not.
2- Monitoring looks for music files - mp3, flac, etc. M3U files are text files, not music files. They contain -links- to where the music lives.
3- In order to create a playlist, the files contained within are (typically) already in your library, so a playlist file in the library makes no sense.
4- Playlists are found in the playlist node and, as previously stated, already have the tracks in the library.
5- Unless I'm completely misunderstanding you, this is not a bug. Nor is there a need for it to be on the wishlist.