Initially, the beta was restricted to a few places like Korea, Hong Kong, Taiwan and Thailand. Now, Google Play Games beta will also be available for players in the United States, Canada, Mexico, Brazil, Indonesia, Philippines, Malaysia, and Singapore. During the initial beta phase, the minimum specs requirements of the application was quite hefty, requiring an 8-core CPU along with a dedicated GPU. Fortunately, Google in its good wisdom has now reduced the minimum requirements to a more reasonable setup.  Our broader goal continues to be meeting players where they are and giving them access to their games on as many devices as possible – Arjun Dayal, Director, Google Play Games

Minimum Requirements 

Windows 10 (v2004)Solid state drive (SSD)IntelⓇ UHD Graphics 630 GPU or comparable4 CPU Physical cores8 GB of RAM10 GB of available storage spaceWindows admin accountHardware virtualisation must be turned onCompatible PC device and configuration

While with this expansion the Google Play Games beta is available in most regions, many significant markets like India and China are still excluded. Google will likely skip the beta for other regions and directly have a official launch after the beta phase ends.