I've been looking for the answer to my question but haven't come across in any of the posts I have read...
What does the Dream Whip do in the recipe??
Since Dream Whip is a whipped topping I'd say that it makes it light, creamy and fluffy. I use her recipe 99.9% of the time and I've never made it without the Dream Whip. Of course w/o the Dream Whip it would just be another shortening based buttercream it wouldn't be Indydebi's recipe.
I've tried her recipe with and without the dream whip before to answer the same question. I personally found that with it, it's a LOT easier at crusting but made it a little thick and hard to ice the cake. I also thought it made my buttercream a little gritty, not a bad thing to me though. It does add some flavor because without it the buttercream was less flavorful but it was easier to spread, just not as easy to use the viva paper towel method on. Hope this helps!