To me resisting during a robbery has nothing to do with money. I keep hearing that it's not worth getting shot over $x.xx dollars. When someone has a gun pointed at you, it's not about money anymore.
That said, I understand people wanting to play it safe. In this video, the best time to fight back, IMO, was as the crooks walked in with their guns. Seconds later, the guy was on the floor with 2 guns pointed at his head. If you go by the idea that you should comply with crooks with guns pointed at you until it's obvious or imminent that they will shoot, this is obviously the time to fight. But at that point, his chance of survival is pretty slim.