I don't mean "the only way" as necessity, I mean as preference.
Look at some of the vehement responses to the OP. Really, GDKP is essential to experiencing these games?
As far as efficiency, hacking the game would be plenty efficient. Doesn't mean it's not a violation of the letter or spirit of ToS. There is still a thing as considering the ethics of actions taken as players. And that's before turning to the point made by Kralljin about economic effects.