Supposedly for training models to generate gameplay videos, like what Microsoft (and others) have presented [0] recently.
[0] https://www.microsoft.com/en-us/research/blog/introducing-mu...
[0] https://www.microsoft.com/en-us/research/blog/introducing-mu...
Not to mention the huge amount of voice samples and webcam footage you could use for more typical voice cloning, text to speech, human avatar creation, etc