The Adam & Eve myth is a beautiful myth, full of deep meanings, only if someone sees it just as it is; a myth. If one sees it as a ...historical account, they miss all the important aspects.
Of course they would choose the tree of knowledge above all. It is the same with the Greek myth of Prometheus. Knowledge was the forbidden fruit in his case also. The very case of early mankind is engulfed in those myths. Knowledge of nature, taming of nature's forces, self-awareness, were the unexpected gifts that natural selection gave to Homo sapiens. However, the ultimate gift of self-awareness ("they knew they were naked", says Genesis) came with a dreadful price: the awareness of death. All life forms die, but only Homo sapiens, with the evolved gift of self-awareness, is aware of the eventuality and certainty of his own death. That was the 'punishment' that God gave to Adam & Eve.
Man, far away from his primate past (a time of blissful ignorance), came with the knowledge of his self and his mortality. This enabled him to reach unprecedent intellectual heights, enabled him to conquer the earth, but cursed him with carrying the 'original sin': the awareness of his mortality.