Why it's on the list: Swapping out the barbell for dumbbells on overhead presses works each side independently, which is great for balanced development. The range of motion is also a bit longer, which can help maximize muscle growth. Pressing in a seated position also removes the lower body, allowing you to focus squarely on the shoulders.
Seated Dumbbell Press Variations for Shoulder Development:
In your workout: Do it first in your workout for solid, heavy sets of 6-8 reps. Going heavy? Have a spotter help you get the weights into the starting position and give you a spot (or even a forced rep or two) as you push toward failure.