Why would they sponsor this for you?

Someone has to pay for it and if their product requires an API key anyway...

It seems like Google, of all companies, can afford to let prospective developers at least try the thing they want you to pay for. I think they have the dev power to sufficiently rate limit as necessary.

Frankly the way Google has been advertising their AI offerings shows they don't care about the consumer market. I hear great things about their LLMs, but for some reason I never try them, and most people haven't either.

This is a small group within Google doing experiments, they are probably trying a different approach after the MusicFX app experiencing heavy usage and needing to limit users. They didn't have a way to supply your own API key for that one

You can easily try Gemini for free in a number of other places

Google can afford to run this model (a bigger one, actually) in their search results when I don't need or want it. Why shouldn't they run this tiny demo backed by their least expensive model? The total cost of running the project for it's entire lifespan is probably less than the value of two weeks of a single engineer's time.

Yeah agree this is a bit nuts from a company trying to promote their model!

So they can save money and use it as a sales funnel.

I appreciate the simplicity of a system that allows you to provide your own API key. All the complexity of authentication, rate limiting, cost capping, scaling, is offloaded to someone else, and you can just focus on the essence of the thing that you're building.

It's Google asking for an API key to a google service. "Simplicity" here would just be them letting you run the demo. Like yeah, all of the "authentication, rate limiting, cost capping, scaling" is done by Google, it's a Google page running a Google service.