I just bought a Vita-Mix Vita Prep commercial blender (basically this thing will turn rocks into powder). One of the first things I did was put some regular sugar into the blender and instantly turned it into fine powdered sugar.
This got me thinking: is there any application where powdered sugar wouldn't be preferred to regular sugar? Commercial powdered sugar has some corn starch in it to prevent clumping, which might not be desirable to add to whatever you are making, but homemade powdered sugar is just pure sugar.
Obviously if you're making any type of drink, powdered sugar wins: it dissolves instantly. But what about cakes and cookies? When you cream the butter and sugar, would the aeration of the batter be effected, aand if so, for better or for worse?
I may ask this question on rec.food.baking, too...