So, D6, the WEG system used to run their excellent Star Wars game, and later exported to a generic D6 system (the latter is available through Drivethru RPG, but they're down for maintenance as I write this, confound it) had a problem: damage and damage resistance.
In the 1e version of the game, any hit resulted in a stun, no matter how insignificant the hit. If you got stunned, you got knocked prone, and unable to act for the rest of the round. You could easily stun-lock the rancor with a weak weapon, just standing out of it's range and plinking it every time it tried to stand up.
In the 2e version of the game, you ran into another problem: The Blaster-Proof Wookie. Every time you were hit, you rolled your Strength to reduce the damage. If you rolled higher than the damage, you had no effect. This wasn't too bad, until you got to wookies, who could have a 6D Strength.... while the average blaster did 4D. Chances are, your wookie wasn't taking any damage at all.
Now, the generic D6 version introduced a new rule. Instead of basing your hand to hand weapon damage on your raw Strength, it was based on half your strength, or half your Lifting skill (which was based on Strength). The default rules are that you removed the pips (so 3D+2 was considered just 3D), cut the number of dice in half and rounded up (so 3D+2 Lifting became 2D melee damage). Personally, I tend to count the pips and divide by 2, with a full die counting as a pip itself (so the aforementioned 3D+2 would be 11 pips... 1D is 3 pips, 2D is 6, 3D is 9, plus 2), and that works out to 5 pips in DR, or 1D+2; it makes every increase potentially meaningful.
Somehow, I also reached the conclusion that this applied to damage reduction as well, but through the Stamina skill, not Lifting. I cannot, for the life of me, find where this might be, and suspect it might be a house rule that we cooked up. But it neatly deals with the problem of the Blaster-Proof Wookie.
A Wookie with 6D Strength and no improvement in Stamina has a 3D damage resistance roll. Still sizable, and he's likely to resist most of a 4D blaster shot... but he's also wise to take cover. If he ups his Stamina to 8D, he's likely to resist all of the 4D blaster (4D v. 4D), but he's still likely to want to take cover, just to be sure.
Now, you may be trying to tie this back to my just-posted rules for improving skills in D6 through use. Which you should. But, using Stamina (or Lifting, for melee damage) in this way is unlikely to increase your skill, because of the very high thresholds involved; you still base your threshold off the base skill, not the reduced skill. So the average human, with a 2D Stamina, has 1D Damage Resistance, but getting XP for Stamina requires passing a 10 Difficulty check... between the Wild Die, character points, and Force/Fate points, it's certainly POSSIBLE to hit a 10 Difficulty with 1D... but it's going to be rare, and you might be better off just spending the CP necessary to flat out improve your Stamina when you get a chance.