By that logic, we wouldn't have gotten pronouns, but they're in, and they surely helped boost sales. A lot of players play for the role-playing aspect than the metagame. Nothing is taken away from players who don't want it. Those who are concerned about "weight balance" can stick to heavier races, armor, and spells or even walk more slowly. The skeletons work fine, too.
Pronouns take almost zero work to implement, as it's just a matter of assigning the old male/female flags to the "Identity" option and recording a few lines here and there for the "Other" flag. What
would have taken work to implement is dynamic NPC responses to your pronoun/body combinations on the same level as the ones they've already included for races, but that isn't a thing that's in the game. BG3 will acknowledge your pronouns but it doesn't actually do anything with them, because doing anything with them would involve a lot more work, and a much more direct narrative acknowledgment of the idea of pronouns that would open the social-issues can of worms far wider than just including them on the character sheet does.
EDIT: This is not an objectively bad thing; Larian made the conscious choice to just write the immediate game-world as not really having strong feelings about gender identity (although it is a bit weird how people can just guess your preferred pronouns accurately without any prompting).
