I don't understand the story of the man who killed 99

So there's a story of a man who killed 99 people which I'm sure many are familiar with. When Allah sends the angels down and they measure the distance the man was to the town of sin and compare it to the distance he is to the town of "attaining forgiveness", I don't understand the logic behind doing this. Wasn't the man's intention and **action** by being on his way to forgiveness enough? Also, I don't understand why he needed to travel anywhere in the first place to complete his repentance. As far as I know there are 3 conditions of repentance 1) regret 2) ceasing the sin 3) firm resolve to never return to the sin. There's nothing about travelling to a special place so that Allah can forgive you. So I'm wondering if someone can explain this story to me.