Every legitimate use case for AI. It is a way to mark legitimate work done using AI tools as inferior.

This might be acceptable if it prevented or limited nefarious use cases. But it does no such thing. It doesn't help at all on that front actually and is not a problem that can be solved by technology alone.

I view SynthId as more of a method of control. It's a way for Google to label work produced by an individual using their tools as their own.

I much prefer open models that let me be creative, write code, etc.. without trying to control/track/mark me.