There is a significant difference between the two. In college it takes a unique skill set to be a potent scorer from the perimeter. At the collegiate level defenses are geared to take away a scorer by putting a strong defender on him, taking away his strengths, and by using more sophisticated schemes to limit the time and space that a shooter has.
In the case of Parker, he flat out gets college buckets. At 6-foot-3, Parker isn't the biggest off guard in the world, but his natural athleticism and ability to use screens makes him very difficult to guard. Parker has the unique ability to come off a screen, catch the pass, rise off the floor, and shoot all in one motion.
He is able to do this because of his excellent footwork. The type of footwork that Parker possesses is rarely seen in high school wing players. Along with the footwork on his shot, Parker has two other key aspects that make him very difficult to guard and will translate to the next level.
First of all he is effective without the ball. Most of the players who struggle to make an adjustment from high school to college do it because they have to have the ball to be effective. That isn't the case with Parker. He has an excellent feel for the game and knows how to move without the basketball in order to get open. Not only is it movement off the ball, but it is movement with a purpose. He reads screens well and knows how to set up a defender to get that extra space.
Once he has that added room because he is smart and knows how to move, Parker shows the second unique factor that makes him so tough to guard, a quick release. It takes Parker virtually no time to rise and fire. The release on his shot might be the quickest in the class, and in college that is important since help defenders get out to shooters quickly and can make life very difficult on a shooter if it takes him time to load up.
With his footwork, understanding of how to move without the basketball, and quick release Parker has fundamentals to combine with his elite level athleticism to be a factor in college basketball. Even though he will be just a freshman playing with other talented players, look for Parker to put points on the board right away for Coach Kevin Stallings and the Vanderbilt Commodores.