Batman The Animated Series is a show that comics fans hold very close to their hearts. And with good reason. Not only was it miles ahead of any of the other animated shows of the time, it still holds up pretty well and it was remarkably faithful to its comics source.
None of which really has anything to do with this video. But it does go a long way to explaining why someone would spend a considerable amount of time re-creating the intro to that show as a live action sequence.
And they've done a pretty good job of it too, only the closeup of Batman's mask lets slip the low budget this was obviously done on.