You think IQ is irrelevent? Irrelevent to what? Look what happens to people who have a low score: they end up being duped into believing ancient fairy stories.
I wouldn't swap a high IQ for artisan skills. Bob's beaten me to it re Mozart. The musicians whom I know are conspicuously bright academically.
In the context of the question, IQ would be irrelevant if, as you put it, I was happy either way. However, I like being smart but I do know that there are things in life that are more important than being able to know what comes next in a number sequence or what "knife is to....". The amount of snobbery shown by people who know what shape comes next is staggering.
Mind you, I know quite a few people who, whilst they can crimp off a thesis before lunchtime, I wouldn't let wire a plug.
[Passing over the attempt to resurrect the flawed assertion that religious people are somewhat stupid......]
I wasn't talking about artisan skills. I was talking about being an artist. I can learn to make nice things but to be innovative, I'd take that over being academic. But then, it's perhaps a case opf the grass is greener.
What I do know is that being a thinker, it don't 'arf make you miserable thinking about everything.
To answer your last point; I know several musicians too and some are very bright (in an academic sense) and some are less so. They are all as musically gifted as each other even if they'd crash and burn on Mastermind.