I don't understand why people object to it as a marketing selling point - it's a new(ish) payment method that's expected to become more widespread over time. Selling your product to a retailer with "Hey, it does this too" can't be a bad thing?

>> I know people don't use their phone to pay for things here

Where is here?

I've seen folks in London using their phone to pass the Oyster/underground gates, and I see people at work use their phones every day in the on-site eatery. When I brandish my phone at the McDonald's drive-through for a coffee, the staff don't look at me like I'm crazy, they hold out the machine. I'm really not sure why you think that it's objectionable.