Yeah it does. You say that controller differences could be an obstical, well the GBA controls are nothing like the GC controller. But that didn't stop Nintendo selling a GBA Player for GC and it didn't stop people buying it either. You say that the GC will be cheap when the N5 comes out (to be honest I don't even understand why you think that matters at all but anyway..) GBA was also cheap when GBA Player was released.
The only thing that it doesn't discount is wether Nintendo will spend the time or money to make it built in backwards compatibility with N5. That's a valid question.