The inventory-checking robot is an interesting pivot for Bossa Nova, a company that is 11 years old and originally focused on robots that could balance on a single ball (it spun out of Carnegie Mellon where the original Ballbot was created). They struggled to monetize it and made toys, which they then sold off and tried to figure out what to do. They ultimately moved away from their special technology entirely to work on inventory. It seems like a huge market, although I wonder how well it works since its vision is largely limited to the shelf item at the front and it likely cannot tell how many there are most of the time. A much simpler solution I've seen at many stores is to have a simple electronic system for each item and it keeps count of how many there are, I imagine each of these costs around a dollar (although you need hundreds or thousands). It's also simple and reliable, of course the robot scales easier for mega-stores assuming it can handle larger inventories easily.
I think Mashgin has a really fascinating idea which is to automate the checkout counter at grocery stores, although I know nothing about how their algorithms work.