I use the arc line to check obstacles, such as trees. Tip: once you think you have your shot lined up, switch to avatar view (you see your avatar holding the club) and go to the mini map on the right and click on the aiming arrow and hold (careful not to move it). You can now see if the arc is intersecting with trees without having the aiming arrow move. I will also use a reverse camera view, if available; not the "reverse view" that it defaults to, but click on a camera facing back toward where my avatar is standing, and click + hold the aiming arrow to check my potential ball flight.
Keep in mind that wind can/will alter that potential flight path.