Maybe there was no special reason to use Google Cloud DNS, or the other Google Cloud services I use, with Google Domains. It's been so long since I set this all up that I honestly can't remember. But I wouldn't be revisiting any of that but for this announcement that Google Domains is turning down. Now, in the process of finding a new registrar, I'm revisiting all of it.
I'm a tiny customer, less than a rounding error for Google. But this still seems like a strategic error to me. How much can it cost to run a domain registrar? How does this weigh against the goodwill and trust gained from maintaining an important service you've implicitly promised that you would maintain?