Take Exhibit A here - We shall call him, from now on, Dave Minion.
Now you can see the differences in height. This does have an advantage. You can stuff them into a space a lot smaller than someone of average height. The downside is they do tend to eat a lot more than what you would expect. What Dave lacks in height he does excel in his lifting capacity. Need an anvil (all sizes), rocket launcher or even, your ever faithful, Doomsday Device moving from one area of the cave to another then Dave's your man.
You may think that you need more than just Dave. This may seem like a good idea until you look at what happens when you end up with too many. Rioting and accidental firing of heavy weapons ... I'm looking at you Dave for this one.
Finally,if you don't believe me saying that a small, hand picked, band of loyal minions isn't a good idea but a large horde is better I give you exhibit B:
I will say that if you do have mass hordes of minions then the odd mistakenly fired rocket will not damage your work force.
Image of The Minions & trailer © 2010 Universal Studios. ALL RIGHTS RESERVED
Despicable Me is UK cinemas from October 15