It sounds gimmicky when you add on top of the 3 item, 2 day, and 5% off restrictions that it's only on select products and valid in select stores. Nice headline news, but shouldn't Amazon be looking to find people who'll become long-term users?
This is finding long term users. It's getting people into the habit of checking Amazon's prices using their phones. Generally, Amazon is competitive enough that they can beat brick and mortar prices, especially when you take sales tax into account (in some states, at least).
It's also trying to get people who don't normally shop online to try it out, under the assumption that once they do it a few times, they'll feel more comfortable doing it in the future.
