condi chrono [PVP]
Depends on what you wanna do. Sage definitely more for healing, but I use Carrion for Condi Chrono, and run Illusions and Chaos as my other two traitlines. Just does more damage over time.
If you run Inspiration instead, and use your healing well a lot, Sage could help. Personally I just find that Mesmer support is less about healing and more about Boons and CC.