Trajectory shows the golfer how the ball will travel, then hit the ground and bounce along the path of the shot.
The projected trajectory assumes the path of the ball if it were hit with perfect power, accuracy, with no curl and other mechanics at play such as wind.

In simple terms, the trajectory shows the path of the ball if you hit it perfectly under default conditions.
Higher trajectory will show a longer projection of how the ball will travel after landing.
Just remember. The trajectory is not a guarantee on how your shots will play out, so adjust your shots according to various conditions!