The utility of leather may also come up in other factors, unrelated to the attack tables.
Like, if you are in clothes, and I'm in soft leather. . .
We run away from an army of goblins through brush, then push through a thicket of thorn bushes, to stumble/fall/roll down a slope, arriving at the bank of a river, we think we've escaped, and assess ourselves. . .
Standing on that bank, we'd both be dirty, but while I might have a few scrapes or thorns in my head or hands, you should really be shredded up bloody and perhaps nearly naked, clad in tatters and rags.
As a GM, it's often to your advantage to be wearing something tougher than clothing when running around in the wilderness, often for reasons having little or nothing to do with combat.