happy gilmore

Padraig harrington uses the happy gilmore swing for this main reason.

Using the happy gilmore swing it maintains a correct transfer of weight throughout his swing.
A problem that re-occours in Padraigs swing is his inability to load up his right leg in the backswing. This becomes very noticable when at the top of his swing his lead leg flexes forward more due to the weight being placed on it, as a consequence Padraig leans his spine towards the target slightly, what we call reverse spine angle. This type of reverse spine angle is commonly seen in golfers who try to use the stack and tilt method.
When Padraig gets into this poor reverse spine angle position, He has to compensate for this in his downswing. He tilts his spine angle back away form the target to give himself room to swing his hips torso , arms and club back to impact. This has the effect of shifting his weight in the opposite direction of the target. This is not good for power and speed.

If you have problems using longer irons or woods off the tee try having a go at the Happy Gilmore swing its fun and it really helps