Very, very convincing and well put together. I can only think of one potential issue – that is being in a congregation where you are the only one doing this… could it possibly be creating a funny-looking situation that may be misconstrued as praying to a different entity?
I highly doubt anyone would think you’re praying to a different entity, unless you set up some odd picture or 3D object in front of you while praying. It’s much more likely they’ll think you’re just crazy or looking for attention. We shouldn’t abstain from keeping halakha because of people’s misconceptions or baseless assumptions
as to our intentions.
The only reason I would abstain from doing this publicly is IF the ground is too dirty, not enough room, or if I think there’s a significant chance doing so will cause real disturbance during prayer, with someone yelling out “asur” or the like. So far this has only happened to me once, out of I don’t know how many times. I do refrain from prostrating when praying in predominately “back-hat” minyanim or in any other situation where it causes stress levels so high that I wouldn’t be able to concentrate during prayer unless I abstain.