It seems to have good results for me. People remember my usual order and are more friendly. It seems to work best if you're subtle about reading their name tag so by the time they look at you and interact with you, you can just use their name very naturally. If you're a regular customer and you remember their names, that works even better.

I won't say I've ever gotten anything out of it (I get free extra cheese on my pizza sometimes?) but it's a far more rewarding way to interact with people.