But that's just a bullshit promise (in the sense of not being anchored to any commitment), no different from a politician saying some policy initiative will create jobs because that's how the economy works.

SMS does leak metadata but guess what, that leakage is going to continue because people aren't going to just cut off their SMS-only-using friends and relatives. Now they'll be leaking Metadata from an even less secure app, so the user is in no way better off.