Thanks, that's what I thought and was trying to figure out if I missed any reason this was staying on the front page given it's just a re-branding of an existing open source solution.
GCGS provides a lot of functionality over the top of Agones. The big win here is that while Agones works great within a single Kubernetes cluster, it requires a lot of manual work to orchestrate across multiple clusters.
This is what Google Cloud Game Servers brings to the table - flexible ways to orchestrate and manage multiple Agones clusters around the world, and the Fleets of warm Game Servers on them.
We also work really hard so that is it's easy to move from open source Agones -> GCGS, but also move back out of you no longer want our management layer.
There's more stuff on top of that, but I hope that helps clear things up
Honestly, your comment is much clearer than most of the linked article.