Jim,
Believe it or not-- the loads I prefer, and use the the most in muzzleloaders (and CF rifles, shotguns, pistols, air rifles, etc.) are never the "fastest" "lightest" or "heaviest."
Any time you look at a rifle it is a system (IMO)-- a combination of weight, handling, scope (or not), velocity, type of bullet that gives the individual hunter a blend of performance that suits him, his style of hunting, and gives him (or me, as the case may be) great confidence in the chosen system's ability to harvest game under the conditions at hand.
There is no particular glory (IMO) in harvesting game with the bare minimum (sure, a .22 magnum will, and has killed deer) or a .338 WinMag (used by a few friends, actually).
A return is a return. If four cents worth of loose powder gives an increase in game taking ability, what is the problem? As few shots per year as is fired by most muzzleloaders, the price of a "Happy Meal" either way, per year, is not going to change the national economy either way.
It's a loooong, long way from topic of "#1 Cause of Poor Accuracy".
If someone decides that 150 grains of pellets is part of the best muzzleloading system he or she has for taking a moose or a caribou, why should that bother anyone? The powder, rifle, bullet, etc., is the fraction of the cost of any big game hunt.