问个小白问题,butter's smoking point and baking temperature

请问一个问题,我平常喜欢用的油比如橄榄油和黄油,smoking point都很低,可是为什么用这些材料的点心,烘培温度都比smoking point高呢?是因为混合了其它材料,所以到不了smoking point吗?比如黄油,沸点只有250-300华氏度,但是有些recipe's baking temperature is 400F, is that healthy? Thanks!