Yeah i'm fairly skeptical about the whole 'matrix-powered phone' thing, matrix the company hit funding issues not that long ago and status.im just threw them a cool $5m presumably to try and fight off telegram and so I would expect that development effort will go into that rather than into purism's offering.

Purism have a huge problem in that they want to meld old school telephony and new things like matrix into the same stack, which there is currently no obvious solution to and so they'll have to invent one. And don't say telepathy because theres a very wide gulf between what matrix can do and what telepathy has support for.

As for Audio/Video calls on Sailfish, theres a couple of developments. The latest gstreamer has a native webrtc plugin I've been investigating getting it working with gst-droid. Theres also qtwebengine support which is on the list for Sailfish 3 which we might have better luck with plugging into the android camera HAL.