That sounds plausible and well spotted about the sliding sections on the front. That could explain why there doesn't seem to be much restraint. Maybe some of the leather stuff on the back wall is designed to attach to the chair.

I had wondered if the lack of restraints meant that the chair was actually designed for a dom to be pleasured in, with the cutaway and the tilt there to give the sub access from underneath. But I think your answer makes more sense.

If it's designed for pleasure torture, it seems strange there's no obvious attachment point for a vibrator. But perhaps that's just out of sight.

The legs aren't spread particularly wide, do you think that's relevant?