It will definitly be a nice improvement. And because it is an improvement I don't think it will be in MAME. However he said he plans to implement this with neogeo games as well, which I think will benifit even more from it.
As long it is not enabled by default it will be a nice graphical filter. Yeah it is highly dubious that MAME will ever touch it, but looking down that pathway maybe the CPS2 driver should be removed altogether considering raster effects are not yet present.