You're Correct!

Having established the key set up pieces of good posture and a neutral grip, aligning your body parallel to the target to hit the ball straight is also a key piece to having a great set up position.

As a general rule of thumb, the club face dictates the start line of the shot with the clubs path compared to the direction of where the club face is aiming, creating the curvature on the ball. By aligning yourself too far left or right will encourage the club to travel in that direction, which is great if youre trying to shape the ball.

When aligning your body, you want your shoulders, hips and feet to run parallel to each other and the target. These alignments accompanied with the club face aiming at the target should encourage a neutral, straight ball flight.

Next time you are practising at the range or out on the golf course, try this drill. Place a club on the ground to aim along, take your set up then take the golf club and place it across your shoulders, then hips, then knees and check if they are all running in the same direction as the club lays on the ground. Set up with good alignment and notice how it becomes easier to swing the golf club in the desired fashion.

By aligning your body parallel left of the target you are encouraging a swing in that direction. If you were intending to hit a shot that curved to the right, then swinging left with the face just to right of the clubs path would produce a shot which started left of target and curved back right towards the target. To hit the ball straight, aim parallel to your intended target.

Having your alignment mis-matched will cause all kinds of problems and result in many compensations during the swing to counteract these poor body alignments at set up. By setting up with your hips left and body right, a right handed player would struggle to make a good turn on the back swing and most likely would result in the arms lifting to achieve a sufficient length of back swing swing position.

It is true that your impact position will differ from your set up as the golf swing is a dynamic motion where we are creating torque and speed. But this doesnt mean to say that the set up isnt important. Your set up plays a huge role in dictating the way you are likely to take the club away. Set up correctly to dictate your desired swing, which should lead to less compensation during your golf swing.