The convenience argument is hard to make with reason - to some extent, you have to try it and see if it makes a difference for you personally. For me, it has c

The convenience argument is hard to make with reason - to some extent, you have to try it and see if it makes a difference for you personally. For me, it has changed my shopping behavior at Whole Foods from rare, carefully planned visits, to more frequent visits to pick up smaller numbers of items. The reduction in overhead for picking up just a bag of coffee and taking it to the express checkout feels pretty dramatic, even though it might not be that much shorter in wall clock time. Battery life seems like a genuine concern. I have an iPhone 6+ which easily lasts me all day, but I could see this being an issue on phones with less battery capacity. I will be curious to see whether the apple watch can still do payments in it's reserve power mode. As to trusting Google - that's a personal choice. It clearly doesn't benefit you for them to have your purchase data, and I wouldn't use a Google owned payment service for that reason, however there are a lot of people who experience Google as being able to provide better search or Google Now cards based on knowing more about them, so would be happy to give them more information.