2D Games to visualize your reality from a different perspective.  Similar to reading a book versus watching a movie.  Where your subconcious mind fills in the blanks which are not spelt out.  Similar to how when you dream and you hear a noise in your bedroom.  And your subconcious mind will incorporate that noise into your dream.

In some cases when I have had the option to play the upgraded 3D version of and old 2D games, I prefer the 2D version.  Because I do believe it has some strengths over the 3D interface.  2D appeals to your imaginative subconcious mind.  Whereas 3D is more directed to your conscious which is reality based.