If you mean freestyle as in freestyle BMX, sure it will work.

There reasons riders prefer their SS over their multi-geared bike (if they have one) are many and personal. For me it started with simplicity and maintenance - I'd rather ride my bike than work on my bike. With as many miles as I was logging and the conditions I was riding in it was more hassle than I wanted. And I'm not even a maintenance fanatic. The single speed reminded me of my BMX roots. You can build a light bike without even trying or spending much. It frees your mind so you can concentrate on the ride. I could go on and on, but you just need to try it. It's not for everyone, but many try it and are hooked.