Sign in - Email or phone number

It depends on what the application use-case. For instance an app for payments, I would prefer phone number but for an educational, social, productivity or news app I would prefer email.

During the sign up process if I'm presented with a screen that requires my phone number and no other option then I will close out the app. If it's an email option I'm much more likely to use the app because I can use a spam account and or any of my other emails.

I always prefer email. Somehow my phone number feels a lot more personal and as I have more than one email address, I can easily decide which one to use depending on importance of the product/service.

I would prefer email. However, sign in with Google account or Apple are pretty convenient as well.

In my home country a service carrier can actually sell your phone number to another person meaning that every single service attached to it automatically goes to the new phone number owner. No joke! I've actually experienced that change once! But that's rather an exception I would say. So, yes, emails are better - IMHO :)

I would prefer phone number as it's convenient to the user. There are other options as well to sign in like password-less and OTP-less authentication instead of FB or Google login.

You should use your virtual number through @cybtel for sign ups so that your personal data remains safe