Just curious, why is that a deal breaker? It seems like a mild form of anti spam protection, potential 2fa backup, and a way to uniquely identify users.
What I've long been curious about is whether the service provider can derive a subscriber identity using the number. I mean of course the mobile network operator knows I'm me, but does Bluesky? Or is it merely a valid mobile number to them?
Unless the network operator or the ISP sells/gives your identifying data to Bluesky, that can't happen. It should be super illegal ofc, but in the US anything can happen...