At the risk of repeating myself, when I started rinseless washing it was a winter desperation thing, and the car was usually covered in road salt grit. I would pre-spray with normal 1:256 rinseless, and it didn't really seem to do anything, so it seemed pointless, so I stopped doing it. Well, maybe I still did it during the winter, but not in the summer. Then later you notice some wash marring on the sides and wonder if that was from those winter washes, and well, it's done already.
Then you get a new car and you think...gee, all the other guys are pre-spraying, maybe I should try that again, and more recently for me it DOES seem to be doing something, whether that's my better sprayer, or better products, or higher concentration...but it seems like a reasonable thing to do, if the car is dirty enough.