I don't see the difference between recreational skier and racer as clear cut. I personally like to draw a fuzzy line around "performance skiing". All racers of course, but pros as well as anyone interested in carving blacks for instance etc would fall in the "performance" category and should definitely be interested in being able to ski like "that".
I don't see a need to be "low in transition" except in relation to the performance that one is looking to get from the next turn: the more performance, the lower one
tends to be. Performance generally defined as a function of carving, turn shape and steepness: on this scale of performance skiing, those at the lower end (beginners/intermediate) would get the same benefits from flexing as racers do, but proportional with their level of performance.
So, I prefer to look at it not as aiming to "be low" but just aiming to be flexing at the end of the turn...
as much as needed or functional... so there is "flexing" and there is "deep flexing".
Like
@markojp noted, without getting too deep into biomechanics, we
can put the skis on edge when the legs are long in transition, but that would be by dragging them on edge from the hips, i.e. with the upper body, leading to a certain type of skiing, mostly upper-body driven (with hip dumping or with extra inclination etc).
To allow us to ski with the lower body, i.e. roll the ankles on edge and all that good stuff, some flexion must exist in the legs - specifically at the beginning of the turn. Otherwise we can't actually ski with the feet, as there isn't enough leverage in the feet to tip the
entire body on edge...
Imagine walking downhill without flexing (without bending the knees at all) - it is possible to some extent, by overusing the hips and putting more strain on the back whatnot, but... why would one choose to walk or run like that... or ski like that? How fast can you run downhill without deep flexing of the "outside" leg ? The most efficient way to run, one that we all discover instinctively, is to flex the forward leg and allow the hips to travel almost straight forward.
Same function with skiing, in my mind: skiing without flexion at the end of the turn is the same as running without flexion. It's also the same as skiing moguls without flexion over the bump: works somewhat if the bumps are shallow and far apart (i.e. low-performance skiing) and it doesn't work as well with bigger more frequent bumps (i.e. performance skiing).
Even a small flex out of the turn makes a big difference. In bumps or groomed alike. And the more carved and the shorter the turn shape and the steeper the hill, the more we need to flex.
that's my story and I'm sticking with it