Jesus penalty for sin need to include physical and emotional pain because for it is better, if God should will it so, that you suffer for doing what is right rather than for doing what is wrong.

For Christ also died for sins once for all,the just for the unjust, in order that He might bring us to God, having been put to death in the flesh, but made alive in the spirit.

It is done so, for the mankind to realize and visibly seen how HE loved and  ransomed  us from SIN though HE was mocked, Jesus still there for us.

Spritual separation from God most of us doesn't known it,It is just between GOD and HIS son Jesus. so, I think there's a need to show to mankind how it feels being executed for us to remember HIM how HE died for our sins.

This was to show that Jesus would show us how much He would suffer for us. We should then be thankful for His great suffering as a way to show how much He loved us, and He even though is God, would suffer in pain like how a normal man would feel.

By showing us this ultimate sacrifice, we will then acknowledge His grace, love and greatness as a man of God.

Jesus suffered physical and emotional pain because even though he was the Son of God he was also at the time of his death on the cross human.

Anytime a human being suffers we feel both physical and emotional pain, that is why I believe that his "penalty for sin" had to include not only spiritual pain but physical and emotional.

It was the BLOOD HIS shed blood cleansed sin once and for all so he had to endure the physical pain as well as emotional pain.  I THANK YOU LORD FOR ALL YOU ENDURED SO THAT WE MIGHT HAVE LIFE ETERNALLY.