When and/or why would you use a noncrusting buttercream? Sorry if this is a dumb question, I just saw something mentioned on another topic and started wondering.

It tastes much better..not so sweet. To get frosting to crust, you have to put way too much powdered sugar in it.

Snarkybaker, I <3 your name!

But to answer the question, crusting "butter"cream is all powdered sugar and Crisco. There may be variations, but that's the 2 primary ingredients.

Non-crusting, or Eurpoean buttercreams are actual buttercreams, made with real butter, sugar and eggs.

Crusting takes a few minutes to make, and is super easy. It's also cheaper and easier to work with.

European buttercreams take time, patience and require cooking. They are harder to make in quantity and you have to really practice when decorating with them.

Crusting has a really long shelf life.

European only has a few days and Americans are afraid of them because they contain eggs (unfounded).

Some people are so used to the crusting that they hate the taste of real butter in European buttercreams, which if you do a search here, it's the primary complaint. They don't like working with it

People that like European buttercreams hate that "fake" icing taste, and the grit of powdered sugar (which is me). I feel it's more gourmet and high-end, and I worked really hard to learn to make and use them properly in my everyday business.

But basically it's a matter of taste.

I think the noncrusting is way easier to work with.

I use real butter, eggs and sugar in my buttercream. once all mixed and flavored I add 1/4 cup of cornstarch and let sit for a few min. once cake is frosted, I let it dry a bit before I smooth using the Viva paper towel method. Works perfect for me here in Colorado. Its not too sweet. Everyone loves it.
I only add the cornstarch for faux fondant.
Personally I prefer it not so sweet, but to each their own. I omit the cornstarch for when I don't need it to crust.