What does it mean to ski that line cleaner? Often people mean carving cleanly without smearing. Not a lot of speed control in carving which is why racers carve at 60 mph on relatively not that steep of stuff compared to some of these narrow shoots. So maybe you mean something else, and it could be arbitrary personal preference without any real advantage. The nice thing about POV is that it's super easy to get the footage. Rather than mince words you can put it up and say this is the better way of doing it. You'll still get an argument, but at least the argument will be further along
Cleaner here means don't make a K shape in order to get the downhill ski on edge so much. Feet under body more. Part of the reasoning is aesthetics, a big part of the reasoning I think is that quickness turn to turn will suffer when you need to be fast if you do that. Also I think that the steeper and nastier it gets, the more this technique is gonna shine through and be exponentially less pleasureful for you as a skier and less effective.
You don't have to carve 60M radius turns to have good technique... the ski just needs a bit of persuasion sometimes... some coaxing... some forward pressure to make a gorgeous short radius turn. Cheers. BTW, this video is not real deep powder skiing and I think my comments would not apply as much to deep powder skiing. More for steep, nasty conditions or less steep terrain. Maybe I can find you some POV video as you asked.