But hey it just can't be really compelling if it is Apple device only.
tl;dr - yes, a compelling video chat software must run well on all employee devices for real success
Petition: Keep your promise to make FaceTime open source https://www.change.org/p/apple-inc-keep-your-promise-to-make...
Legal battle may be to blame for Apple breaking Steve Jobs’ FaceTime promise https://macdailynews.com/2018/06/07/legal-battle-may-be-to-b...
A wonderful collaborative experience could just be a USP for the platform. FWIW, the now obsoleted iChat was way ahead of the curve compared to the current iteration of FaceTime in group settings, anyway.