Re: Carmichael CT-200 drum throne anyone?
...while it may work in theory it doesn't look too comfy. I think that gap may get to feel a bit awkward over time. Not enough padding or support under the buttox.
The gap floats your spine, which is a sitting experience that does not allow (greatly lessens) compression of your vertebrae and yields maximum balance.
There's correct support b/c you're supporting the weight of your frame and innards with your butt cheeks, not your tailbone/spine. Its an incredible experience really.