> So if an emergency came up (and I was still employed) I would just save a smaller % of it.
i mean that's not really an emergency.
An emergency is one such that if you weren't prepared for it, you can't handle it. For example, losing one's job can be considered an emergency (a short one, if you're in high demand).
A medical emergency is a good example of an emergency - to which you prepare for by purchasing insurance.
So by saying that a person's portfolio would perform better by ditching the emergency fund is just the same as saying 'take on more risk and get more return'.