When the shit hits the fan you want your inside information flow to be at least as fast as what is happening outside. In most organisations this is not the case.
Conventional hierarchical communications systems are too rigid and there are too many obstacles to information flow.
Internal social networks are noisy and messy but so is life. If you have a big enough, mature enough, fast enough set of internal conversations taking place then you will be better able to work out what is happening and what to do about it.
Yes it may be too late for this current set of challenges, and it is still counterintuitive for many in positions of authority, but we can all do better than resorting to WhatsApp the next time the shit hits the fan.