it's the only way to make the call - it's so obvious that it shouldnt be remotely controversial (because almost every HC does it this way now)
the reason you go for it the first time is really simple...
if you don't get it, you have more time to game-plan around not getting it and you know whether you need 1 score or 2 scores with more time to adjust one way or the other
if you kick the pat then you have learnt nothing, you still need a 2pt conversion, but now you've got less time to adjust if you dont make it
sure you've kept it a 1 score game for longer but that's meaningless if you're going to lose anyway