I'm curious about what apps would be available since PWA is something new in the app industry and also, how will developers sell their apps? If it's lightning fast I might accidentally buy something I don't want.
I think you have to be very careful if you don't want to buy something that you don't want. And besides, there is always a confirmation for all purchases that we buy. Sometimes, there are many confirmations just to be sure that you are really interested to buy the product. If you haven't entered anything using your credentials, I don't think, they will push with the transaction.
This is funny. Even if it is lightning speed Im pretty sure there will no no direct purchase without asking you for confirmations once or even twice. And besides i dont think you will buy something that will not interest you.