If we (pragmatically) accept the idea that art is in the eye of the beholder (computed by your beliefs and views of the world) then machines can’t make art. All they make is things we don’t expect, and then we assign artistic value and meaning to that output, like seeing beauty in a splash of paint or shapes in clouds.
It is tempting to push this point to actual art too, but with a compromise. The experience of an art piece is definitely an internal and instantiated (different from once instance of persons to another), but as a human, the artist carries an agency and provokes a reaction.
I would argue that an art piece by a human is a prompt, where one by machine is a bug.