Ignoring my ignorance of the science, I've always felt that the left/right assessment overlooks the top brain/bottom brain, so consequently ignores the harmony needed for keeping us in balance.

It suits humans to compartmentalise our self-development: we like to have order in our lives, to know who we are/where we are, perhaps that's a consequence of logic, having something tangible to go on.

Labelling the left side of the brain as used for one thing and the right for something else plays to that sense to make head or tail of things. It's just that by ignoring the top/bottom arrangement the tail gets forgotten in the quest for knowledge. We become top-heavy and the stress and strain leads to us becoming emotionally (and spiritually) disconnected, we end up living mind over matter, instead of mind and matter.