Realism is only valuable in any work of art when it aesthetically heightens the experience. In a milsim you include as much realism as you can while balancing it against its playability as a satisfying fantasy. With Zelda and fantasy adventure games generally realism is not a meaningful priority, rather you aim for diagetic plausibility and consistent art direction, balancing that against playability as fantasy. In fact because realism is not a priority in the fantasy adventure like in it is in a simgame, it has an easier time synergizing its design aesthetic and its playability. I don't know what OP means by realism in Ocarina, but it must be something like the animations of cutting grass, or breaking jars, or the appearance and behavior of water? I would say it's more like diagetic plausibility, ie. things look correct for the world they're in, things appear real to the reality they're in.