Edges makes bigger difference in ski touring or more appropriately ski alpinism. Meaning tricky steep slopes where you sometimes switch skis for crampons and ice axe and put them on backpack, wildly varying conditions on the slopes. Or using ski crampons when its less extreme.
There, any advantage is very important, ie how precisely you put skins on skis to leave that little bit of edge for... edging, at least thats what we call it. I don't think it makes a massive difference there how sharp your edges are, but in steep icy/crusty slopes where your skis don't even leave a mark as you pass, only crampons a bit, everything helping is more than welcome. I never clean them thoroughly though so edges are rusty, 10-15 years of moderate use of skis makes no difference to me.
Also, in usual piste skiing in resorts, if you go really fast, at least relative to rest of skiers, and slope is a bit icy, sharp edges make a lot of difference in how stable skis are in turns. There even I can feel difference between dulled and sharpened ones.