Leatherface is a pussy for using weapons
Seriously, why is he considered to be one of the most iconic serial killers? He's a coward! It's simple, just take away his weapons and he'd be nothing. He uses weapons because he knows he'd be weak without them. If you take away Leatherface's weapons, a body-builder, wrestler, martial-artist, or a boxer would be able to take him down in a hand to hand combat.
If you use weapons, that means you're weak.