I was on the beta testing team and have been using Beeper for a little over two years now.
The convenience of having an application to house all of your chat networks is amazing.
Luckily, the DMA has a heap of requirements around what their messaging interoperability will have do. For one thing, it will enforce the providers to not downgrade any encryption along the way, so FB etc will have to handle messages without them being decrypted first. There are some great videos that the matrix foundation put on their YouTube channel of talks that go over much of this.