To evaluate a hand when they first see it, most players count their points.
The 4-3-2-1 scale originated almost a century ago and is widely used still. Other scales, which claim to more accurately reflect the trick-taking power of the honors, appear from time to time. The Robertson 7-5-3-2-1 scale and the unwieldy 13-9-5-2 scale may be better in theory but lack the virtue of simplicity.
Good players know the shortcomings of the 4-3-2-1 count: Aces and kings are undervalued, queens and jacks are overvalued. A hand such as A K 8 7, 6 5 4, A J 8 7, 8 7 is worth opening because the values are prime and the jack of diamonds is more likely to win a trick when the ace supports it. But few players would open with Q J 2, K J 5, Q J 4 3, Q 6 5.
In today's deal, South's leap to game was a misevaluation; his nine points included four jacks and a queen. If South had held J 5 3, A 10 9 7 4 3, A 3, 7 4, his chances at four hearts would have been good. As it was, he had four top losers.
After all this discussion, you may not be surprised to learn that South made his hopeless game. West led the deuce of spades, and East captured dummy's king and returned a spade. South took the jack and led the jack of diamonds, faking a finesse. When West played low, South next cashed three clubs to discard the queen of diamonds. The defense got only the A-K of trumps.