Yeah, without lights it's tough to see what goes on in the back of the enclosure, let alone, what goes on at night when I'm asleep. Soon, I'm going to get a security camera to spy on him at night. I'm really looking forward to that.
Another reason I think I don't see him use them more is that he doesn't need to. He only has 14.5" of height in the upper terrarium, so he doesn't need much help to climb up. He could probably periscope directly into his sky hide. One day, when I have more room, I'll build him an enclosure with more space to climb.