You probably understand this, but just to emphasize for all those people who are still skeptical: it doesn't just not make sense, it's impossible. At least not without spending many, many thousands of dollars worth of resources, and then still only have a limited chance of success.

A merchant can accept Bitcoin zero-confirmation payments not just because his customers are such nice people that they won't scam him for a few bucks (or a few hunderd bucks). He can accept Bitcoin zero-confirmation payments because of how Bitcoin works.

Again, there's a lot of theoretical debate around this (I know Peter Todd mentioned a few tricks) but in daily practice, this is what it boils down to. Bitcoin works absolutely fine in point of sale situations.