Problem with those little grinders is time. When doing large batches, or grinding more than one time, it can take painfully long time and the meat can start to warm.
I'll also add that learning to make things like hotdogs and ground and formed bacon can save trim time on some meat pieces. When I butcher I have a hotdog pile and a burger pile of meat.
Like I stated in my other post the grinder will grind faster then I can stuff meat down the throat. I have no problems doing 50 pound batches of burger and considering I purchased some rubber insulated gloves to keep my fingers from going numb from the cold meat I don't have a problem with it warming.