Not just text, but also images, music, video, etc.

You are correct that "AI detectors" (if they were accurate) give a very crude indication and omit nuance. That sucks. But, from my point of view with creative works, such a thing would be better than nothing.

At least if there were such a detector, then there would be a way that I could be comfortable with at least some new works. That would be an improvement over the current state of things, where my default position has to be to ignore new works altogether.