How are we noobs? This is a perfectly valid way to unlock the characters, as it is added itself by Sakurai. Besides, you would need to unlock characters the Brawling way if Subspace you cannot do at a short time. For brawling, just battle 10 matches and boom, you get two characters (That is, you beat them).
I see nothing wrong in this method. Besides, if we were to cheat, we'd use all those shifty tactics such as Wavedashing, or quitting the game. That is cheating and is unfair. But we just need the characters at a fast time so we can do things such as...fight online buddies and practice for big items. Besides, you fail if you're a no lifer on Brawl (Playing for hours on hours for example).