They must offer something considering they make a living as a group.
It is interesting and is nice music to have on while you do shit. Its not music you would put on to dance to or anything like that but it has its purpose. I prefer stuff like Stars Of The Lid when it comes to Drone music but the heavier Drone Metal is nice too. Just general ambiance etc.
It's like post rock or post metal.
EDIT
For example (WARNING THIS VIDEO CONTAINS TITTIES DO NOT CLICK IF YOU ARE AT WORK NSFW)
http://www.youtube.com/watch?v=FCOe5iMz_OI