I think you don't get it. It's not about annoyance. It's about the complete unreliability of any online service today. All and every customers show (and should rightfully show if they don't yet) complete distrust for a good reason.
You are asking my phone number today and next day I will find it out in the open because of your and others' businesses don't give a .... when it comes to security.
And don't tell me that's only a minority or the exception. Because that's just simply not true.
500px, Quora, Facebook, Twitter, Equifax among others all have been hacked at one point or have been exposed as unreliable and untrustworthy. It's just simply not a logical proposition to trust any online platform with private and/or sensitive data.
We do care about security and hash the phone numbers after sending the verification SMS (we only need to determine whether a given phone number is associated with a locked account - a hash is good enough for that).
Our problem is that criminals open hundreds of accounts with fake data and stolen credit card data, abuse our services until we get abuse complaints or detect it and lock them, then repeat that. This leads to legitimate customers suffering from bad IP reputation and is expensive to clean up.
Requiring phone numbers and blacklisting known throwaway providers has been extremely effectively in preventing this, without generating complaints from our legitimate customers. We don't want to use browser fingerprinting or other intrusive mechanisms for detecting sybil registrations.
You are asking my phone number today and next day I will find it out in the open because of your and others' businesses don't give a .... when it comes to security.
And don't tell me that's only a minority or the exception. Because that's just simply not true.
500px, Quora, Facebook, Twitter, Equifax among others all have been hacked at one point or have been exposed as unreliable and untrustworthy. It's just simply not a logical proposition to trust any online platform with private and/or sensitive data.