Interactive raytracing is the future both in mobile and desktop. My project http://clara.io, an online 3D modeler + renderer, recently gained the ability to do embeded interactive ray traced 3D embeds using V-Ray (one of the best and most accurate renderers in the world).
It is cloud streaming, this is because we do not want to be limited by the CPU/memory capabilities of the client. V-Ray is an amazing renderer, but for complex scenes it can require +32GB and use up to 40 cores or even clusters of machines. We want to virtualize that infrastructure for our users.