There’s more of it? Same reasoning we use for every other compound we put in our body: More growth hormone equals more goodies from that, more testosterone/steroids equals more goodies from that, etc etc.
We’re not building a trike here – we need some serious tools to make huge gains. More insulin in the body equals more ability to break down carbs, more weight loss and in a surplus, more weight gain, better recovery.
You could apply this statement to basically compound talked about on this forum. Why take testosterone? Why not just let the testicles sort it out?