And that is good reason to flat mount off-piste oriented skis: easier balance and greater security in 3D conditions, who wouldn't want that? Why do you have to make it a put down? I disagree that it's purely about what people can and can't do, but rather what people want to do. Frankly, striving for big angles off-piste is a niche pursuit, we shouldn't be surprised or haughty about the corresponding niche use of risers on offpiste skis.
Liam, it isn't a put down. It is using physics and observation of skiing style to determine why a skier would prefer a particular setup. It is not easier to balance on the ski mounted with a lower stack height; it is easier to stand flat on it. It is actually more challenging to balance on that ski when it is tipped on edge. So who wouldn't want that? Answer: A skier who is putting their skis on edge as the primary method of turning. The shorter setup offers the feeling of stability when the skis are flat to the snow. The skier who typically prefers a flat/low-stack setup, is not putting their skis on edge as the primary method of turning.
The "snow feel" difference is negligible - especially for those with good snow feel. The edge feel difference is extreme. This discussion has nothing to do with striving for big angles off-piste, and everything to do with using the skis to turn skier instead of using the skier to turn the skis. When it comes to lacking ski use, it is rarely a question of desire to use the skis, but rather a question of ability to use them. A common theme among the best skiers is their ability to extract performance out of their skis. A taller setup makes it easier to use your skis to turn. A flatter setup makes it easier to not use your skis to turn. That is physics.