Cloud gaming is when games are run on a server and streamed to your home. Combine chromecast and cloud gaming, and you suddenly got a huge platform, with much more users than xboox one/ps4. And since it's google ,it would probably run android games which there are tons. This could make the platform preferable for AAA gaming.
One more element that could be important in this is microsoft's "project spark" which let users build games with amazing creativity and amazing graphics. It's still in beta , but when it's release it could be a huge force in gaming , especially together with VR.