ok, so lets think about this in an absolutely ideal sense, where this product works perfectly as advertised.
if your skis are 100% repellent to liquid water, what are you sliding on?
Water is an interesting element because it's both a lubricant AND an adhesive. When you're skiing, your skis are really sliding over a very very very very thin layer of water (melted snow from the friction of your ski moving over the surface- i mean like really really really tiny amounts of liquid water, but liquid nonetheless). This is why, when you take your skis off and pick them up at then end of a run, it's very likely to be at least a tiny bit damp on the bottom.
in the sense of being an adhesive, the more surface area that is on the bottom of your ski for water to interact with, the slower you are going to go. This is why we wax skis- not because of any incredible speed properties that wax has, but because of the nature of a PTEX base- PTEX is a plastic polymer that is filled with tiny little air holes when solid. it's not smooth.-> without wax to fill these holes, all they do is create a LOT of surface for water to interact with and slow your progression. a well waxed ski has the MINIMAL amount of surface area available for water to adhere to.
(this is why you tend to go slower in slushy wet snow too, there's more water slowing you down in the snow. you go faster on rock hard ice, because its a lot harder to friction melt it to liquid water)
I'm not a physicist or an engineer, and I don't work in materials science- this is just the way that I was taught skis work from working in a tech shop for a few years.
so, ideal sense: Liquid Water is 100% repelled. you do not move all that much, because you aren't generating lubricant to slide down the slope on.
less than idea sense- the shit wipes off in a few seconds, because there's nothing in it that helps it adhere to PTEX, and you move like normal. no better, no worse.
pray for snow.