Keeping your action compact limits the scope for the action to go wrong.
A bigger swing back from where you hold the bowl often involves taking the bowl around your body and way from the line you have aimed meaning you then have to refine the line as you deliver. Whilst this is achievable, it is harder to replicate consistently.
Starting your action with the bowl lower but in line with the line you want to bowl, usually be being a little to he side of your body makes it easier to hit the line.
Top Tip: A golf coach once pointed out to me that you don’t hit the ball on your backswing so keeping it slow and controlled would help me hit the ball better The same principle applies to delivering your bowl.