The reduction of ship tracks due to regulations has caused the planet to warm up faster, especially in the Atlantic Ocean. This unintended consequence has provided an opportunity for scientists to study a geoengineering scheme in action.
Rather than "reduction of ship tracks has caused the planet to warm faster" I think it's more accurate to say that the planet was warming faster than we thought, but the ship tracks were masking the problem.
Since the tracks are caused by the high sulphur content in the bunker fuel, it would not be a good idea to suggest that they are beneficial.