We cannot really move on unstable surfaces. Say while skidding on ice: the body is locked up, the brain freaked out and we cannot really move.
This is why in skiing, we talk about creating a platform: an engaged edge of the ski creates a platform, more or less stable, on which we can move and stay balanced on.
We stay in balance by pushing against the earth: mostly sideways. Go on, stand up and get a little out of balance: your feet pushed sideways against the earth an got back in balance. You can't push against the air.
Step forward: again, you push against the ground to move the hips forward.
A skidding ski is not a platform, not a stable one anyways: there is nothing to push against to get back in balance or start a movement.
This is why priority number 1 for all performance skiing and racing is establishing an early platform that CAN be used for balance and movement.
Note that I said CAN as you don't have to use it unless you need it. But it's there. It's available.
Here's a great talk from a former US ski team head coach on establishing the platform, as priority number 1 between turns. And the trick there is re-balancing, getting forward again to bend the ski and make it grip.
While we may disagree and split hairs over pushing the hips forward vs pulling the skis back, or whether or not we should "actively push" early, but the message is simple, clear and obvious: you are in control when you're on a stable platform.
I don't not draw a line at racing and he says as much. Racers are usually the keeners that advance skill and practice sufficiently, are used to having to turn often, are looking for the extra zip, plus being perhaps a little bit more nuts than average I guess, but I would call it performance skiing as opposed to relaxed skiing. Like he says: you have to move. It is more energetic than not moving.
Zip to 6:00 and hear the same message we kept repeating here ad nauseam: sure, you can step your turns, can pivot entry if you carry too much speed for what you want to do, they're all valid tactical choices. But any great skier CAN get forward and establish an early platform, as their GOTO turn.
Flat out skidding the skis sideways is not a stable platform. Neither is pivoting the skis (which makes them skid). While these are sometimes needed to control speed or make that impossibly offset gate, the first priority is ending them with a stable platform, so we can regain balance and MOVE.
If you look at your favorite WC skier during a stivot, they are generally completely stuck, like a deer in the headlights, until the skidding stops and they get a grip and can move again.
As mentioned in Types of turns and tactics carving and skidding are not on/off but a continuum of anywhere between say 1% and 99% grip.
The closer you are to the 99% grip, the better and more stable the platform, while the further you are from that, the worse, the more out of control you are.
Brushing is when you are close enough to carving that the platform is fairly stable and you can still have the skis perform.
Well, there you have it. This is what we mean by "creating a platform" or "establishing a platform" -