if evolution doesn’t waste anything then why does limbless lizards still have vestigial limbs and blind fish have eyes?
Those vestigal limbs might be nessesary for the development of other parts of the anatomy.
Or like our long hold view of the Appendix, they actually do have a use we are just not aware off yet.
In any case, they are not a big waste of energy. Not compared to what the brain eats. It is not affecting the survival and reproduction of the Lizard in a meaningfull way, so the "selective pressure" (specimens die before reproducing) against it is limited.
"Actually how can a supposed random occurance favor anything?"
If your offspring randomly develop with +2 too -2 handiworks skill, the -2, -1, 0 and +1 will be selected out eventually, simply by the +2 being better adapted at this time.
Evolution is a mad scientist that tries absolutely everything at least 3 times over. The mutation either flies or dies. Evolution is "trial and error".
Some mutations are +2 Handiworks skill. Some are Haemophilia and never properly weeded out.
And really confusing is that +2 Handiworks might be a loss for any species that lack the brain to use it, so it is weeded out. While Haemophilia might actually make that specimen resistant to certain Illnesses.
For example there is a number of Genetic Disesaes that are nominally bad to have. Except they also make you inately resistant to Malaria. So this can actually be a tradeoff that is worth it.