It allows the smith to make twist in his metal without the metal bending over. If you have just one handle the force will twist and push over the hot steel. Having a two handle approach allows for even twisting and keeping the work from bending away from the smith.
When you shoe a horse, the shoe is nailed to the bottom of the dressed hoof. If the bottom of the hoof is not nice & flat, the cold shoe can be twisted a bit to better fit the hoof contours.
I looked on this website and It said that twisting wrenches are for twisting metal into different positions.
It's for tightening and loosening pipes.
I can't seem to find anything about this tool I found in my garage it's called a twisting wrench I know it's a blacksmiths tool but I can't find any thing about it.