Yeah that would work, but I can see why he is trying to do it this way. I have the same thing for my taunt macro and what is nice is that it allows taunting/BoPing without actually selecting anyone. You just keep the mob targeting and whoever it has agro on will get the effect. Essentially just works like a ranged taunt on the monster when under the hood it is casting on a friendly. It is great to not have to take the moment to try and figure out who it needs to be cast on only to find the mob switched again.