Why is Google launching a TLD and you cannot purchase it through Google Domains? It's currently showing as "Not Supported" even though they link to Google Doma

Why is Google launching a TLD and you cannot purchase it through Google Domains? It's currently showing as "Not Supported" even though they link to Google Domains from get.app. It's mind-boggling to think they couldn't come up with a "coming soon" blip if somebody tries to look up a Google-owned TLD on Google Domains.