I am super excited for these gaming hiring funnels to take off due to your first reason. Dollars to donuts there's a ton of unidentified talent out there that is being filtered out due to those biases (I would also add in academic pedigree bias which is correlated with economic/cultural upbringing). Granted these types of funnels also select for those who have free time to play games so they are not perfect.
Knack, the other company mentioned in the article, seems to have profiles with pictures and names that I assume are visible to hiring managers and others. In my opinion that's a bad move. I want to see a completely objective view of how a candidate is performing without age/experience/appearance getting in the way. These gaming funnels aren't perfect solutions but they are certainly a step in the right direction.