In a TTRPG context, I think it's less about trying to make races completely alien -- which would probably be unwise between players' varying RP abilities and the fact that they need to interact with all the human-types -- and more about game designers boxing themselves in with not wanting any races to have race-specific penalties, nor any race-specific significant benefits (mechanical or cultural) and ultimately winding up with a milquetoast blend of gnomes whose strength rivals that of half-giants or elves who you'd never guess had millennia of intellect and wisdom behind them or whatever. They all wind up feeling much the same because they all are pretty much the same, and differences are mainly cosmetic ("rubber foreheads").