"To raise awareness about the vulnerability of buildings to terrorism," apparently! So: Now you are aware, that buildings are vulnerable to terrorism. Something else that raised awareness of buildings' vulnerability to terrorism: 9/11. And another thing that helped raise my awareness that buildings are vulnerable to terrorism: Looking at buildings.
Goodwin also apparently climbs buildings to let the world know that he is a cancer survivor. He used "suction cup-like devices" to get to the top, pausing to drink water given to him by residents of the tower.