I was asked for my email while paying at a sports store. I declined. The sales person was confused as to what to do next since "the system" wanted an email addr

I was asked for my email while paying at a sports store. I declined. The sales person was confused as to what to do next since "the system" wanted an email address. I asked her if she wants to sell me those products or not? Turns out the system works without an email address too. Who would have though?