I think phone is a hassle. You have to pull it out of the case, put the password, open the menu, go to the lightning app, scan some qr code, click pay... hopefully your battery is fine and you have signal. People already pay with cards these days. You can just give the cashier a card, they scan it, and it's done. You don't have to run a node at home if you don't want to, you can use a 3rd party service. It's not like full nodes are running on mobile phones anyway. I think all 3 methods should be supported and standardized at Point-of-Sale locations (phone, card, paper bills), and let people choose. The way I see it is Bitcoin: Be your own bank, Lightning: Be your own credit card company.