VMCG means Jack all once you pass it and by V1 you are either on or above it.
Dangerous assumption, especially on a contaminated runway where the lowest possible V1 is used. Now consider having an engine failure at 98kts, just passed the V1 of 97kts but very shy of the full rated Vmcg of 116 kts and increasing the thrust to the maximum possible to get that darn thing airborne. There will be a very swift and violent sideway departure of the runway why still being on the ground. It doesn't help that some airlines do not publish the Vmcg table anymore, but it is understandable if one considers that one table would probably hurt more than help if you use three different thrust settings.