There are no discernible advantages, other than those of aesthetics. I bought Muramasa, knowing it was a pretty average game, because it was beautiful. I really would like games that exist, even if they're bad, to be beautiful, and 2D has some of the most beautiful games to this day. Making 3D environments is far more difficult because you're working with textures over blocks, which are difficult when creating natural-looking animation. Bastion however does manage it, though it's running on an engine created specifically for the game (and it uses 2D art as an overlay running on a 3D engine).Wouldn't a 2D environment versus a 3D environment be different when the 3D characters are inserted? I am mostly asking because I think it would be better to have a dynamic 3D environment with a dynamic camera than a fixed 2D environment with dynamic 3D character in it.
What are the advantages of using 2D environments exactly? Besides making it easier for the developers to compose beautiful scenery and manipulate a static picture than a dynamic 3D scene?