Michael,
If you know you have 163 yards to the pin and that is your seven iron distance, then 99% of the time, you would grab your seven iron and hit a dart into the green.
But if you didnt know, you'd be forced to "feel" the shot taking into account the clues the course naturally provides. Since you cant throw darts with GPS precision when you dont know the yardage, you may decide the best option is to hit a low shot that runs onto the green.
Just think about chip and pitch shots from around the green. Most people dont calculate the exact number of feet a chip is. Instead they play the shot by feel, sometimes with a 60 degree wedge in the air, sometimes with a 7-iron on the ground.