I work in central London. There's a supermarket below my old office (Sainsbury's opposite Holborn tube) which is around 1/3rd tills. There are around 30 in total, of which around 20 are self checkout. Nevertheless, at lunchtime and rush hour, you still have to queue.

This technology would be extremely valuable to a shop like that. More choice, more customers, better shopping experience. And employing staff for 3 short-lived peak periods must be expensive.