What you want is the Bill Russell shot blocker, who controls the tip and gets you possession. But still, most blocks are five feet from the room, so that's a high percentage shot. If they get the ball back and wind up with a contested jumper, that's not a bad trade-off. You also might get them the ball with just a few seconds on the shot clock.
Then there's the deterrent factor. If you have a shot blocker who gets two or three a game, he's also altering another four or five a game.
I definitely wouldn't argue that shot blocking is overrated. That sounds like something a fan of a team without a good shot blocker would say.