Good supports helpt their carries in lane. The best supports win their carry the lane and their team the map with ward control.
Ward control, lack of items, levels are huge disadvantages to being a support. However if those players can handle it and the team understands that their support ia one ofbthe bettee and listens. It will be an easy win.
Remember, Wards = Enemy control = team doesnt die to ganks as much = less farm for enemies = advantage.
You also now know when and where to gank. A support that wards has one of the biggest impacts on a game.