My previous post was unapproved, so here it is, until it can be approved:
Showing horses is about presenting your horse doing what it naturally does, in an enhanced, more difficult way and see who can do it best.
Spinning itself doesn’t has to make sense, it is an exaggeration from a handy horse being able to move quickly over it’s hocks, then brought to a high level of competence in reining spins.
Roping developed as a way to treat cattle you found with injuries and more important, screw worm infections.
Blow flies would lay eggs in wounds and especially in new born calves navels.
Those grew into flesh eating maggots that would eventually kill it’s host.
Screwworms were terrible on wildlife and then when humans brought cattle here, also on them.
Best way to treat as many a day as you could find was to rope them to catch them and treat them.
That too, when people had time on their hands and wanted to show off their skills, arena roping developed.
Is not the same, roping outside is about sneaking in and catching, then riding around the calf and letting the rope wind itself around legs, back the horse and the calf would fall over, legs taken out from under it and you could run and jump on it before it got up, tie it down and treat it.
In the arena, roping was made for time and changed to what is today, not like pasture roping.
Similar to why we jump horses over obstacles and why higher and higher and in more difficult ways?
We want a horse you could use to travel faster than on foot and some of that included jumping whatever you came across, logs, ditches and such.
Once making jumping a competition, we train and jump higher.
Some gaited horses were comfortable to ride across the land as people used them for transportation.
As people liked their horse look flashy, the more animation and leg action those horses had, the more they liked it.
Some made competitions out of that, some gaits were considered best and the more exaggerated the horse moved, the flashier, some decided to compete to see who had the fanciest of all.
Saddlebreds were one of those breeds and so we have today their many gaited horse classes with those horses showing off their stuff in shows.
People just enjoy their horses and doing things with them and competing seems to be part of what humans do, with horses also.