The addition won't matter much if you're comfortable with NFC-based purchases, but it could help expand Android Pay's reach. Many people don't know their phones can handle tap-to-pay shopping, and this could expose them to the concept for the first time. It's also a sharp contrast with the likes of Apple Pay and Samsung Pay, where you typically have to use first-party tools to get started. Google is clearly betting that the more open nature of Android Pay will give it a larger footprint.