I thought this was a joke, but apparently not. Plenty of us don't ever use the e-brake with dedicated track vehicles. This is because they're not really "emergency" brakes, they're parking brakes and you don't use them for the reasons Glyn mentioned.

As for using them as a legitimate emergency measure, I think it's definitely time to think about that. So here's the scene: you're deep into the entry of a corner when you realize you are have catastrophic brake failure (I say that because you have two independent hydraulic lines that would have to fail simultaneously; but that's another matter). Now you decide to pull the e-brake as a way to stay safe? Not only is it not going to stop you, it's almost certainly going to spin you unless you're going straight on. The move is just as likely to make things worse as it is to help - and I suspect it's really more likely to make things worse. You've just locked up your rear tires right when you're in a mood to take evasive measures...I'd rather not.

Best,
-j