The video goes into detail on how the brain does the thing that it evolved to do. And that thing is to enable the organisms to successfully negotiate its environment.
The brain being a short-term modeling engine that predicts the future is made very explicit in the video by Dr Wolpert.
This type of analysis about how the brain evolved and what it does and how it does it is critical to understand cognition at every level.
Before the brain is anything else it is an engine that allows a motile organism to successfully move around. After that an analysis of the brain from the viewpoint of how creatures with a brain can be successful and how natural selection drives the evolution of this engine is covered very well in Michael Schemer's book "http://www.michaelshermer.com/the-believing-brain/".