Ofcourse a flat ski has the least friction, but flat skis don't make tight turns, edged skis do. The deeper the racer can take it (straighter line) the faster they will go. To ski a straighter line requires a tighter turn and that requires a highly edged ski with sufficient pressure. Inclination is the catalyst that sets the initial high edge angle, while angulation compliments inclination by helping to resist the forces developed later in the turn and maintain pressure on the outside ski. The racer seeks to maintain just enough pressure on the outside ski to get the job done.
A skier inclining with out angulating is not minimizing the edge angle, rather at worst they are not pressuring the outside ski sufficiently. This photo of Ligety shows an extremely high edge angle with minimal if any angulation: http://www.levakhsanov.net/p30655468...CC57#495897687
Of course you can get to a high edge angle while banking, but you need to be going really fast when you do it. Regardless, if you add some angulation to your banking, you will immediately get to a higher edge. Whether or not that works depends on your speed and the arc you are on and how you want to change it.
In your earlier post you said that an early high edge was the key to speed. That's completely wrong. Of course racers often need to be on edge early, but the real key to speed in the course is to maintain your line with the minimum amount of edging. It doesn't matter if they lean, bank, counter or angulate or ski with their feet apart or together. The best racers have good feel for how much edge they need, and good balance skills. Everything else you see comes from that.