I too have always wondered about the decision to use Hydroquinone. Although it has some appealing chemical properties and the molecule itself is quite beautiful, I think the choice may have been driven by cost considerations but that is pure speculation.
Metol and hydroquinone form a superadditive pair but in a low pH developers its main function is to regenerate the metol. This can be seen in Haist's D-76H where the developer works like regular D-76 but without the hydroquinone has a lower capacity.
A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.