Plus F1 cars would need space to put ballast and then they’ll need more fuel to carry that extra weight around which means bigger fuel tanks, therefore it’s a terrible idea.
It’s debatable whether weight penalties actually work, if the car is good enough it isn’t a big problem. Yes the drop in weight for the BMWs helped them move a bit further up the grid but not the Ladas (the Granta doesn’t exactly suit the S2000 regs anyway). Maximum ballast pegged the Chevrolets back a bit but they were still just behind the Hondas which were running at their base weights.