Karl, there's a setting in the Preferences screen that let's the user assign various functions to the foot switch. I'm pretty sure auto punch is one of them.
I don't have a foot switch and have never had the need for one, nor had an issue with using auto punch. As mjk says, it's a pretty easy and foolproof process.
I can see the convenience of using the foot switch, though, if you can't get close enough to the DP or need to have your hands positioned and ready to start playing.