Stream is basically providing an internal Youtube, a place where you can upload videos, control who access to them, and let Stream take care of routing, etc.
Video content is 'difficult' for smaller to medium companies to manage and deliver. Some things are best taught through video.
You may be thinking in just a sense of an office, but this could be useful for Factories or other slightly skilled labour.
Add in basic messageboard/etc from a trusted brand, who most people already subscribe to with their OS and Software.
However the 'anyone' can upload, seems like an HR disaster waiting. And I suspect will quickly be turned off to a limited few to the few that use this service.
They're announcing a small, separate product to validate if there is demand. Then they'll get early users and burn money while they figure out how to make it into a profitable business.