well its more of whats best for you.

DWC + Airstones Just helps maximize aeration and keeps the water from getting stagnant. You can use either by themselves with few problems, but I would say together just makes it all the better, with less maintenance. By keeping the water flowing, you add oxygen, by adding air pumps + airstones for bubbles, you add oxygen. so the more the better your plants you grow, and the less problems you have.