Although they do look a bit crappy and you can't keep an eye on the belt condition and tension as easily, I personally wouldn't run a track car without one.
When you consider it's very possible (and I'm not having a go at your driving ) that the car could be bouncing through a gravel trap, throwing stones everywhere, including upwards into the engine bay, it seems to me a good idea to have one fitted.
7-8 grands worth of engine destroyed to make an engine bay look a bit better, isn't really worth the risk in my opinion.