The issue with this is that I would prefer to see an athlete develop a proper power position and scoop for the snatch rather than try and power the weight up from a less efficient explosion point. Efficiency in the skill is necessary to the extent that it allows you to put up the maximum weights for the application of your training. If for GPP than a good power position is necessary in my opinion, if for SST which is Coach Boyle's game than I'm not certain. I would have to look at the needs of the specific athlete but to me it doesn't make much sense to use an inefficient technique. The only advantage to a narrow grip that I can see is that once its overhead it is easier to support which is why I did it. BUT once you get into lifting real weights it screws you over because your wrists and shoulders get accustomed to supporting from a narrow grip yet you can't get under any real weights. The wide grip now becomes a position of compromise when you attempt to switch over and you move back to less significant weights in order to adapt.
Thats my take on it anyways, I'm pretty new and I don't have a problem teaching explosiveness but maybe I'm special in more than a few ways