I can't speak for slaughter and processing a cow (only helped once at age 10) but when it goes to wild animals more grind = more work for me since I remove the meat from the bone. NOW when they grind, their operation may be to simply omit parts of the cow like the shank, the oxtail, portions of the ribs, etc. so they dont even process is. I would not like that to happen at all but it might happen.
The easiest processing is to break the carcass down to the primal cuts then break them down so if you order zero grind it all seems to me that would be easier since its just the process of break down, break down, slice, package. No debone steps in there.
Again I can't speak for them but when I process my deer and pigs (usually 10+ each year) it is simpler for me to not debone but I usually have to cause I dont have a saw to take a shoulder or a shank and just slice the big cut into pieces.
Hopefully someone chimes in and cures my ignorance of what a farmer/processor would consider simpler to do :)