Retail analytics are a potential use-case, but we've decided to focus on space-optimization for buildings because we believe it's an underserved market relative to the opportunity. There are a lot of established companies doing footfall analytics for retail (using things like WiFi, BLE, door-counters, thermal images, analytics on video surveillance data, etc.).
As for sensor coverage, we cover about 1k sqft per sensor (it'll vary a bit depending on mounting height - higher mounting equates to a wider area of coverage)
Also, what this the average area the sensors cover