Resting in a squat position isn't supposed to take a lot of exertion, it's restful unless your muscles are tight from lack of use of full ROM.
Basically the more hip flexion you get, the less bent your colon is:
Just using a footstool or squatty potty is probably a scam though. I don't see why your butt should be in contact with anything. You need most of your weight on your feet to get the best flexion anyway:
Above is best concept I've seen for conversion (I will buy one some day) because you can hold onto the top to avoid falling backward.
If I were to make one change I would make an overhead handhold to give additional options. Some people's arms might not be long enough to reach the forward handle here. I'd want alternate options (like gymnastic rings) to pull myself up out of the squat if I fell back and couldn't reach the top handle of this device.
All other squat platforms have that glaring absence, just a platform to stand, no handholds for the possible fall of the unfamiliar.
We tend to have really tight ankle-extension muscles which prevent the torsoflexion needed to bring the knees forward beyond the toes for optimal balance.
It looks like poop might drop an extra inch or two which could create a bigger splash. That could be concern for it hitting the underside of the standing platform and maybe the shoes. That's one thing I'm trying to figure out how we could mitigate, like if there was some kind of 1-way splash-trapping device.