"Side gapping" a plug won't offer any benefits, much like hyper expensive plugs offer no benefits beyond extended plug life (despite all the power and mileage they promise).
About all you will accomplish is making the electrode fire off centre, which may contribute to a hot spot on the electrode which will wear it out unevenly and possibly quicker.
Firing on centre causes the electrical arc to fire on the centre of the electrode, where there is more area for heat dissipation. Also with more area it means the plug gap will be less effected by wear. There's more metal to have to slowly blow away with an arc before the gap starts to wear away.
