Synfig focuses on more cartoon based vector animation. What GEGL provides good foundations for doing is video editing/compositing with keyframed properties for filters.
As mentioned in the linked article of this story - having an eco system of applications using GEGL would benefit both these applications and GIMP - since they would be sharing image processing operations and plugins.
As mentioned in the linked article of this story - having an eco system of applications using GEGL would benefit both these applications and GIMP - since they would be sharing image processing operations and plugins.