What is the difference in using Rolled Buttercream over Fondant? What is the advantage of the Rolled Buttercream over Fondant?

I've used both rolled buttercream and Satin Ice fondant on cakes. Personally, I love the Satin Ice fondant and hate working with the rolled buttercream. I find that the rolled buttercream is greasier, has a glossier finish, and tears much more easily. I do still use rolled buttercream for some accents on buttercream cakes.

I have tried desperately to use rolled buttercream with no luck at actually covering a cake with it Well, I actually covered one, but then it all kinda melted/slid off the cake over the next couple of hours. Luckily it was just a practice cake. I like to use it to decorate cookies, but I love MMF or MFF for cakes.