They are secure but often slow. I think the future holds a form of a compromise: you will have a secure wallet similar to bitcoin to hold your main savings. But in addition there will be apps that let you buy credits. Lets say Starbucks credits. You get those as bonuses for your purchase or simply by buying them. Now when you need a coffee, you will just make a selection on your phone and let their camera scan the code generated on your phone. This could feel really unsafe if this sort of payment method could access your main wallet. But by providing buffer wallets you can invest some amount for your convenience. Surely the example is not perfect, I wouldn’t want to illiminate social aspect from Starbucks.