Many a pundit, in trying to add to the appeal of the rifle he was touting, has suggested loading different bullets to different velocities for greater versatility. I even adjusted the loads for a 30-06 so that I was shooting 150, 165, and 180gr bullets all to the same point of aim at 100 yards. What for, I don't recall, as I shoot 165s from my 30-06's except the one time I took one elk hunting with 200's.
In my case, Murphy's law never rests however and I would guarantee that if I went afield, I would be sure to have the wrong ammo along. So, when I buy a new rifle, it is with a niche bullet weight in mind, and I work up a good load in that weight and use it on everything or take a different rifle.
I do think that any idea that sells more rifles and ammo is a good idea. I just hope that Big Green isn't building a dedicated plant to supply this ammo.