What other multiplayer games/options are available when I have a second copy of New Super Mario Bros.?

My kids like to play the Minigames with each other on their Nintendo DSes. If I were to buy a second copy of the game (rather than them sharing one game between them), would there be any benefits or other games or options?

Solution 1:

There aren't any additional games or options available if you play with one copy or two - the only difference would be that you wouldn't have to wait for other players without the game in their DS to download it with Download Play.

The manual for the game explains it here: New Super Mario Bros Manual, if you scroll down to page 32/33. There are just two different options on how to connect, but no benefits for two copies.