The tech behind the tool conceals the fact that messaging is taking place at all. It makes the communication indistinguishable from data sent to and from the app by our millions of regular users.
Reminds me of how the Germans in WW1 knew they couldn't trust their diplomatic codes anymore so they just sent the important messages in the normal, innocuous telegraph system and diplomatic pouches. They knew that foreign intelligence would be focused on the bogus secure messages.