I think the concentration on the target has more to do with you being able to actually finish the shot.
If you are anything like a lot of wide recievers, for example, your mind has finished the shot before the ball is actually out of your hand and suddenly your focus is on the pins, and the shot goes errant. Wide recievers often look toward where they want to run before the ball is even in their hands, and it bounces off their head or pads, though, in their minds, they've already made the catch. The best ones watch the ball all the way into their hands, then move, rather than the other way around, like a bowler focused to make certain he's actually hit his target, then he's free to watch what happens at the pin deck.
In either case, you have to see what the ball does with your real eyes, rather than your mind's eye, and the target focus is nothing more than an aid to help you do it.
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