I don't believe it's "SIM as ID" - I believe it's SIM as complete authentication (i.e. userID+password in traditional systems). (I have my thoughts on THAT as

I don't believe it's "SIM as ID" - I believe it's SIM as complete authentication (i.e. userID+password in traditional systems). (I have my thoughts on THAT as well, you'll be surprised, when it comes to security... we're nerding out about obtuse and obscure end-to-end encryption, meanwhile, majority of those 2bil users don't have a lock on their phone, and now they also have no protection on their messaging :-/ )