Most of those services have a lot more latency than you may realize. I've been looking for a way to stream real-time game video from a friend on the west coast to me in Kentucky, so we can kibitz over voicechat; high-quality streaming video has very noticeable delays at best.
(And it's really bad if the service is optimized for streaming to many viewers at once--Twitch enforces a minimum buffering delay of 10 seconds even for a private, one-viewer stream, and can range as high as 60 seconds in heavy conditions, which really annoys a lot of streamers. If anyone has a suggestion for a good low-latency one-to-one video streaming tool, I'd love to hear it...)
NVidia GRID is probably the best benchmark, especially since a latency optimized data center full of GPUs sounds like a pretty good place to do some matrix multiplication. If it's fast enough to play a game it should be usable for everything but fast motor control.
Have you tried using the webrtc protocol? It streams data without a go between server. You can probably find a website that implements screen sharing, if not its like 100 lines of JS.
(And it's really bad if the service is optimized for streaming to many viewers at once--Twitch enforces a minimum buffering delay of 10 seconds even for a private, one-viewer stream, and can range as high as 60 seconds in heavy conditions, which really annoys a lot of streamers. If anyone has a suggestion for a good low-latency one-to-one video streaming tool, I'd love to hear it...)