It is superior (in one sense) - it gives capabilities lacking in lower IQ people but it comes with metabolic and development time costs so you only get as much of it as can be translated into more surviving grandchildren. Same with any capacity like breath holding ability.
Everything is strictly advantageous - the question is the cost - introducing randomness to the payout doesn't make the costs go away or become irrelevant. Pay x more metabolic cost to have a distribution with a higher mean or don't.