Mainly because it's almost completely impossible.
With Rage, and Bloodfury, and the KSB str aura, he'd still need to roll 5 6's and a 5 to kill the average heavy at arm 18.
And at that point, your model didn't kill the heavy, your crazy hot dice did
I once killed an ironfleshed butcher from fresh with a stone scribe. That doesn't make that a good plan. It just means I rolled stupidly high dice once on a model I had juiced out of desperation.
Most trollblood players don't use the skinner...but some players...well some players just want to watch the world burn.