Not correct. Waxing your bases protects them; waxing PVC and metal protects it too. The wax makes the rail slide more consistently. No grippy spots. When you get hung up, your forward edge can dig in and then you have a burr on your rail. If you want your rail to stay nice longer, use wax.
To OP, I use orange swix. Brand doesn't matter but warm weather wax has worked great for me. I just rub it on the PVC and it slides great. Very predictable with no slow spots. I have also used it on a crappy little skateboard rail. Before wax no slide, after wax good slide. I have not tried candle wax. You could also try bees wax sold in every hardware store. The reason I would go for ski wax though is that it will get on your bases too. If you use candle wax or something else and you don't clean the stuff off and hot wax your skis again before the season, your skis may be butt slow on snow.