It's not a two-factor auth, we ask phone number confirmation because our masters need to contact you to deliver our service. If there is no phone number, our ap

It's not a two-factor auth, we ask phone number confirmation because our masters need to contact you to deliver our service. If there is no phone number, our app is useless for you. So it's perfectly fine for us if you want to delete the app instead of giving up your number, and it seems like a better solution for privacy concerned people. On the other hand, if we allow to login but only request phone number later, this will seem somewhat deceiving to the user. Like we pretended that he can use the app while keeping his info private, while in the end it ends up that he cannot.