Everything begins on the ground, goes one line of thinking. If you can get your horse to do it on the ground, you can get them to do it when you are on their back. Ground work gets your horse focused on YOU, the job at hand, not the monster in the corner, the cute mare/gelding in the next field, the scary plastic bag… etc. Which I would think is a great thing no matter what you do with your horse.
I was moving poles today in the arena to set up a set of trotting poles. I put my horse in the center, told him to stay there according to what he knows from his ground work, and hauled the poles around. Horse stood like a statue, as he knew he should. As I knew he would. He did not move until I told him to, coming back to him, and picking up his lead rope. A very handy thing to know my horse will stay put.
Same horse- went to skip out his stall while he was in it. His neighbor wanted to start a war through the bars, as it was feeding time. Horse was told “over” ( a nifty command he learned in his racetrack days, yes, this is an OTTB) and he went and planted himself along the wall, eating his hay and ignoring his warring neighbor. He did not stir a hoof until me, the wheelbarrow and mucking equipment were gone. Again, a handy thing to have.
I cannot stand ill mannered horses on the ground. It seems to translate into a crappy attitude in the ride. My well mannered horse is a happy and willing fellow under saddle, and is calm and focused. He wasn’t always like this-- when I first got him, he was the opposite. Work on his ground manners and ground work in general resulted in the change. I know which I prefer.