Skin suits are really for time trialists, track riders, and perhaps triathletes. If you aren't racing, there really isn't a reason to wear them. Also, they don't have pockets, so anything you want to take with you is going to have to go in some saddle bag. The Velominati will scoff at you for wearing something so aero but then hanging a suitcase on your saddle.
If you have a tri bike and you are training, then that's fine. I don't think i've ever seen someone on a road bike in a skinsuit.