I see it like all forms of seemingly-structureless music, like ambient, free jazz and other oddball shit like Nurse With Wound or whatever. There's plenty going on texture-wise and atmospherically. I tried typing a lot more, but I really don't know how to explain it. It's an acquired taste. I used to absolutely hate Sunn O))), and I thought people who listened to them were mentally ill (I was, like, 14). Then I listened to them a bunch, and I just sort of got it.
inb4 "Sunn O))) fans are mentally ill"