Gah, this is so confusing, I've got small sites developed for clients many many years old running various maps based stuff off API Keys in my account, now I have to add MY billing information to them or get the client to set themselves up a google cloud platform account and developer and project and keys and ......
Good grief, that's totally impractical to have website administrators, my clients, to do that, even I as a seasoned developer hate trying to navigate around the complex labyrinth that is the Google developer console stuff.
It's all so complicated. I just want a page I can point my customer to, "go here, type in your domain name, enter your credit card number in case you need to be billed by Google for usage, and tell me the API key it spits out".
On top of that, it's still of course totally open to abuse and quota theft, referer checking is not security. I can see a burgeoning black market in api keys forming.