Both are pushing boundaries in mechanical dexterity. Yet one is considered art and another is not.
Others have said this better, but art is an qualitative/emotional thing, not a simply measurable quantity of an object. We tend to use the effort put in as a proxy measure for quality, but when photocopiers and 3D printers and - yes - genAI get involved, that becomes harder or impossible.
Beating Guitar Hero is emotional, but not artistic. Photorealistic drawings could be emotional, and may or may not be artistic. Putting a text prompt into a generative model to make a (frankly terrible) music video for $100 is ... something else.
Beating Guitar Hero could artistic. I don't even know how, but I'm sure some artist could beat Guitar Hero in a way that was somehow artistic.
This terrible $100 music video which I'm not even going to watch, is surely not art. Also I'm totally sure some person is going to spend $100 with an AI and make art. It's very hard, but they day will come. The slop-to-art ratio will be astronomical.
However, consider works like photorealistic drawings of eyes (usually at a very large scale). A lot of people like these, and consider them to be fine art, while others (art critics?) consider them bland. Contrast that with a Picasso flamingo drawn with a single line.
There is artistic value in high-effort, low concept works as well as low-'effort', high-concept works and other combinations. Perhaps what we are all looking for is effort of some kind (I prefer human effort) whether that is conceptual effort or practice in drawing lines on paper.