I am, for example, quite happy to buy stuff online.
However, when I go into a brick and mortar shop, I want to be served by a flesh and blood person. Someone who I can say hello and thank you to and will do the same to me. We might smile at each other - even enjoy a brief joke or some other form of human communication.
Self-service checkouts are fine for those who want to use them. Choice is good. But my personal choice is to stand in the queue and wait. Please don't require your employees to try to cajole me to do otherwise.