I was lined up for a foul shot in HS and while I waited for shot #1 I noticed the shoes on the kid next to me. He was their top scorer. I bought the same pair the next day.
Seeing some fast kid wearing them wouldn't motivate me to buy them more.
Let me expand on this - when I was in high school, I wouldn't care about what spike the state champ was wearing.
But you do. When you go to the store you will not laugh at some brand because you now know that 5 fast kids in your state wear them. So you are open to giving On spikes a shot..brand awareness matters.
My understanding is almost all these deals are shoes, some gear, and travel to a meet. This is pretty cheap advertising.