Exactly! That's what a strong running game does for you. If you're run game sucks those guys don't even consider biting, they're busy clogging up the secondary looking for INTs.
This is a common comment, and I always wonder at it. The defense should be reacting to the formation and tendencies. Even if a bad running back gets the ball, they're going to take him just as seriously as they'd take a good one. Meaning they're going to move up to fill if they think you're running it.
About the only thing having a better running game does is naturally influence your tendencies. Since you're more successful with it, you're more likely to run it more often. The flip side of that is there's also benefit in calling plays across your tendencies.
Overall, I'm not sure there's much evidence to support that a strong running game makes misdirection more effective than a weak one. Though I'd be interested in hearing the arguments to the contrary. I'm sure there are some good ones.