Could also be internal geo location. That’s a solved problem. Sensors on the shelf have already existed for a while in things like warehouses with automated inventory management systems and robots picking up the products. Once the item picked is located and the closest user has been identified, the shopping list can be modified. Seems a bit too complex for a retail store to have the kind of cameras, GPUs locally to achieve the kind of latency shown in the videos. They’ll need a subset of the technology used in self driving cars for that which would make it hard to justify the costs. If it’s an experimental store then that would be fine.
And then what about people with hats?