I was surprised to see that these are based in Unity. Is there a growing community of machine-learning research in Unity, and if so, what's prompting that?
By using Unity, they can create a virtual environment that mimics the real physical experiments. I think this is good, as one big 'cheat' in many AI projects is representing the 'state' of the system in a way that implicitly captures expert domain knowledge - i.e. about what parts of the environment are significant with regards to performing the task. Letting the agent 'experience' a virtual world in a 'raw' form allows it to figure out what's salient - what it needs to remember - which animals also have to do in experiments.
Plus, Unity videos demo really well.