The concerns you raise are true in corner cases, but the general use case should be good enough. Your solution also seems to require mounting one of your devices at the entryway of every room for which you wish to monitor occupancy. Seems like it could be costly, especially if doing so requires wiring power up to it.
That is the other side of our approach, yes. Active depth sensing and on-device deep learning means non-trivial power and speed requirements, so the hardware isn't as cheap as we'd like it to be. I'm not up to date with the latest developments on the hardware team, but they're working aggressively on our BOM and we're hoping to take advantage of cheaper and lower-power SIMD/GPU chips in the future. Our current-gen model works with Power over Ethernet, and right now we're most often selling to customers with large/valuable real-estate portfolios because they can get a higher ROI from accurate count data.
