This is close to Scott McCloud's definition in his book Understanding Comics.

Thanks for the pointer! His definition is very similar and may well be the original source.

a well-crafted spear is not art? that seems almost backwards- art is anything that takes skill to create

the associate of art with uselessness and dissociated aesthetics is more a product of an age of decadence than anything central to appreciation of artforms

A well crafted spear is indeed art - since it doesn't absolutely need to be well crafted, it is that aspect of the spear-as-tool, specifically, that is considered art, and elevates it to that realm. This is why OP said the argument is flawed, because it is. It becomes highly subjective quite fast. But thats the reasoning.

a better-crafted spear will provide more survival benefit, whether by being stronger, sharper, or more reliable when thrown