Anecdotally... I live in a city of just under 100k people and the downtown normally has maybe a few dozen people walking around at night and a few hundred more

Anecdotally... I live in a city of just under 100k people and the downtown normally has maybe a few dozen people walking around at night and a few hundred more inside the restaurants. The weekend of Pokemon go there were 300 Pokemon players hanging out downtown. It helps that literally every storefront is a pokestop. I don't know how much business they generated, though.