You just need a method to run DS code. This can be an already flashed DS, a passme/nopass with a GBA slot card that can be used for the DS (newer EZ4s can not), one of the other means that you don't really want to use for this, or a DS slot cart. Today most would use a DS slot cart to get it.
Flashme itself does not provide a terribly useful way to run code, certainly not commercial games. Its benefits are for most these days the option to not have the health and safety screen and the option to easily boot modified download play games. For any normal use you will want to get a DS slot flash cart which handles all the running of games, including modified ones,
cheats, homebrew and more besides.