If you're looking to hit high pitches or lob shots, you have to release the hands to get the ball in the air. To become better at releasing the hands, take a few practice swings with the hands a few inches apart. Concentrate on making sure your right hand finishes above your left (as I'm doing here). This position indicates I've rolled the hands effectively and have released the clubhead through the ball. A popular misconception is to think that the way to hit it high is to hold the face open. That's not true! By allowing the hands to release, the clubhead will move faster through the ball for a higher shot with added spin and improved trajectory.
The Split grip drill helps train your hands to release more so you can hit higher chips, pitches and lob shots.