The point of the Play Coins in first place is to get people walking as many days as possible. The idea itself sounds great on paper, but it's ultimately dragged down by the arbitrarily strict daily cap. It's incredibly easy to hit 1,000 steps (10 Play Coins), since you only have to walk for a bit less than a kilometer. By the time you get about 2+ StreetPass tags from any place that isn't a gaming convention or Japan, you would've already reach the limit.
Way to go on defeating the premise of Play Coins, Nintendo!
Way to go on defeating the premise of Play Coins, Nintendo!