I'd say the main difference is a human actually thinks and understands what they're doing.
I'm writing this as someone with Master's degree in computer science (in interactive media to be more specific) and had some AI classes at uni and whoo boy, has this whole ai art conversation make me realise the difference in understanding of current ai algorithms between someone who's dealt with them vs folks outside of field.
So, ok, let's start with can a computer think - no, it just does simple maths very fast. Can a computer fall in love was a subject on my first ai lecture and the general conclusion is - we're years if not centuries away from having machines think/have emotions on it's own, if ever, cause we'd first need to fully understand how a human brain works and how thoughts form in it.
So what are the ai algorithms actually doing? They're approximating most optimal solution to a mathematical problem. It's just calculations with some randomness added and a function that chooses the best solution from bunch of random ones.
No thoughts, no intelligence, no artist.