Whats it matter if your 150 out compared to 152 or 153...save the $350...
--How about if you're 150 from the center of the green and it's somewhere around 126-138 to clear the bunker between you and the hole?
--Or it's 150 to the center of the green but the flag is just five paces from the back of the green which you figure is "about" 170 "more or less"? And let's say there's a four-foot dropoff with deep rough back there.
--Or better yet it's a Par 3 where you can't see the bottom of the flag but there's a bunker in front and water over the green and all you know is the card says "#17 Par 3 164 Yards" but the tees seem to be awfully far forward today?
--Or finally, you "think" it is "about" 102 to carry the front bunker and you know you can hit your pitching wedge exactly 104 yards. Is that enough club or is that 102 really more like 107?
Of course serious players just wing it, right? You wouldn't see a good player worrying about the difference in 102 and 107. Heck, that's why they don't even play practice rounds on a new course...