internally balanced 360 crank (BIG PROBLEM) need input

I have been looking at some videos on balancing a crank shaft and can anyone tell me the advantage of internal balancing a crank ?
I agree when the plug came out of the crank that was put in the wrong way that the crank and block took a beating... whose Idea was it to change to an eternal balanced crank
anyway..
[ame="http://www.youtube.com/watch?v=2UNLrXUL49w"]How to Balance internally & externally balanced Crankshafts (Crank) - YouTube[/ame]