Well, what it does from my point of view is accounts for very good defense using UZR, then also accounts for positional scarcity based on their position, adding more defensive value, while comparing their offense to 1B and DH regardless of their position.
If I were to break down how I would weight, I'd say offense 6.5, defense 3 and base running .5
Probably 1 higher on offense than fangraphs weights it, whatever that works out to