The first time a user logs into the HelloCrowd App or your Branded App they are required to enter their email address. Usually this is the only time that they interact with the login screen (email address). Most of our users (99%) will never log out of the App but we have to provide the option if they do logout.
If a user does logout for some reason or reinstalled the App, we require the user to enter a OTP which will be sent to their email address. This is to ensure no one is using their email address to access the App.
Also, when users want to have the App on more than one device, it will require the OTP - This is to secure their profile.