by the same reasoning, an OD that results in only 1 or two steals a game is worthless, or perhaps, worth less. for some reason, most managers in this game find this statement ludicrous. i think the same thing when i see someone trashing SB.
i think the value of SB, in addition to the stat in the box score, is in the shots distorted or otherwise interfered with -- in other words, check out the other team's shooting percentage against a C (and of course other players) with a high SB -- i bet you will find their percentage is notably lower.
SB is not an end-all and be-all to a good team defense, but i do believe it is a very important component.