Right... and I lack the strength to ever get a ball to travel 350 feet no matter how well I hit it, but in large part due to steroids Barry Bonds can hit a ball 350 feet even if he hits it off the end of the bat far away from the sweet spot. He can also swing the bat faster which allows him to make contact with balls that he otherwise wouldn't have been able to react to before.
In baseball, if you can hit the ball hard enough to go over the fence on the fly, it is a huge advantage for your team. The stronger you are, the more likely you are to be able to get the ball over that fence to gain that advantage. The home run records are held by guys who we're all pretty sure took steroids. It's pretty clear that it helps.