Jesus responded to the man's faith and healed him. If there were any doubts in the man as to the identity of Jesus, they were erased. The impulsive proclamation of the man hindered the testimony and work of God. That was His primary purpose at that point in His ministry. When the man disobeyed, He forced Jesus to go to a different place to preach where He was not so well known.
True compassion reaches even to the lowest level.
Compassion is always necessary when working with people because we all fail. We make terrible mistakes, commit terrible sins, etc. But we need to move toward compassion, like Jesus did. When we don't have compassion, it is because we think that we are better than others. We think that they are in their situation because of some fault of their own and we wouldn't have done whatever it was that got them in that position.