It is not so easy for the opener to properly support his partner. He has to take into account his distribution even more than his points. Later in the auction, the way the honors in the two hands complete each other will play a key role, especially in the slam zone.
With 14 elegant points (good Diamonds as a source for tricks, a singleton and an ideal 5-4-3-1) East must support his partner with a jump raise. West has only seven points, but with the precious Queen of Diamonds it is out of the question for him to pass. He has to bid game.
With 11 HCP, East must make a general game try (his partner may well have 14 HCP). West has to hurry back to 3♥ with that minimum hand that has no ruffing values, hollow trumps and scattered Queens.