Statistically, if you fire every turn, you should misfire every second turn. This means that even if you shoot with your sallies every turn of the game, you should only kill 6 handlers. As you probably won't be able to shoot with them for all 6 turns (maybe 3 normally), this number becomes even less. Based on this, you can say that extra handlers usually doesn't pay off.
However, it can also be very handy since most opponents tend to target the sallies with shooting and especially magic. It all depends on how much you are willing to gamle. If you want to have some extra insurance, go for extra handlers if you have the points.