It's a complicated matter because it's (claimed to be) the first system that's doing so well in Starcraft II so it's hard to believe it just has a mechanical advantage. But on the other hand, Google is in a position to throw a lot more resources on training their system than most others, so maybe it's just a combination of having a ton of compute coupled with a slight advantage in how you can control your units.

If that is the case we haven't really learned anything new from Google's achievement: we already know that a powerful computer can do some things faster than a human (e.g. arithmetic). We also know that there are things that humans can do a lot faster and better than computers (e.g. learn human language). The question is if Google's system is getting better at something that computers are known to be not very good at, in this case, strategy, I guess. That would be something new.

Personally I'm still in my default position which is skeptical.