This is something similar to Capcom vs. SNK 2 E.O. for the game cube.
With less real-estate than a regular controller, this allows folk to get off those more difficult ultras by Blanka, Guile, Vega, M.Bison.... those that need you to charge inn one direction and repeat it twice more.
Even though Street Fighter is the pinnacle of serious fighting games, it'll never be as serious on a hand held, so I think it's cool that there making it so that the player can still have fantastical fun with the awesome moves that the Cpu is whipping you with.
(That was longer than it need to be...)