The store you are referring to does not seem to be the norm of any major store I have seen. Take Wal-Mart for example. There are more self-checkouts than manned registers, and there is no "self checkout" discount given to those who use it. Oftentimes, there will be a long line waiting to use the self checkouts. I imagine it will not be long now for a similar practice to arise with fast food checkouts. I can see normal restaurants using Boston Dynamics caliber "Spots" to bring out your food and/or utensils drinks etc. With companies paying top dollar for burger flippers, cashier's, etc, at some point it no longer makes sense to have that recurring expense. The dawn of the AI powered robot is on the horizon, and it will be life as normal for up and coming generations to interact with them like self-checkouts are to us now.