Well its pretty much the same as doing SOME of the big 3. When tapping into that bolt and grounding it in all reality you are taking the (ground your engine block to frame) from the big three....and just using the alt bolt instead. Cant hurt just helping out your electrical system.
These. Alt case is a true ground of sorts in your vehicle.Nothing wrong with it just an improvement in the ground, but I would go ahead and finish it with an upgrade in the alts charging lead and battery to frame and call it good.