This also lines up with our observation that Conversations is generally more reliable for calls in weak service areas or while driving. It seems generally more reliable and for a while was the only one that wouldn't say "ringing" unless it had actually made contact with the other person's device. If it just sat on "calling" but never switched to "ringing", you knew the call didn't go thru, for one reason or another. Signal did eventually add this, but it still feels generally less reliable.