I use the same weight fabric (about 2 ounces per square yard-uncoated) for my backpack and my clothing.
I can’t recall a backpacking trip on trail or cross country where my backpack was exposed to more abrasion/tearing than my clothing.  And the 2 ounce material is strong enough to carry the pack load without failing.
Others use a heavier fabric for their packs. Is it justified or just a few ounces of extra weight?
