Because, y'know, there are quite a few players and DMs who see the stats as more than just 'something that affect in game dice rolls', and actually use them as a key part of character creation, in the background, in the choice of style of play, and in the general portrayal of the character.
And when I say 'quite a few', I mean a hell of a lot..... including everyone I've gamed with in the last 6 years since I came back to the hobby and played RPGs in mainly adult groups.
It might be a key point that none of us ever use point buy, so we don't get to pick and choose in such a 'scientific' manner, we roll the dice, arrange, adapt and play what we have. Because, to us, that's a core aspect of roleplaying... a low Int character making intentionally wrong choices, a low Cha character roleplayed as being abrasive/awkward when dealing with NPCs, a low Str character refusing to attempt heavy lifting because of a 'bad back' or similar excuses, and so on.