Don’t get caught up in the glamours look of these costumes - that is what they are costumes for glamor shots. They are things movies are made of and not realistic for riding unless one is in a costume class or a parade:)
The Nez Pierce Native American tribe is still well known for being the best horsemen on the planet, possibly second only to the Mongols.
Their every day riding tack was sparse to say the least and as efficient as they knew how to make with what little they had. That does not mean it was good for the horse. It only means that’s all they had ; they were (and still are) excellent riders.
This link has some old black and white pictures that look to date back to the turn of the century (1800’s into the 1900’s). The Nez Perce Horse ? Dreamer Horse Farm
There is one foto of a Native American on a horse with a bit and reins similar to what you posted. The horse looks thrilled (not) to have it in his mouth and wrapped under his chin.
It is evident by the black and white photos the Nez Pierce opted for more industrialized tack, once the opportunity was there.
I rode bareback the bulk of my entire life - sliding down river banks, swimming the rivers, digging up the other side. Digging up power lines so steep I had my arms wrapped around my horse’s neck, hoping I didn’t slide off his back before we got to the top.
I did all that with a low port curb bit and leg/seat cues that I did all the training. I was raised on horses, that type of riding is not for the novice.
Born in the late 1940’s in the United States, I had plenty of opportunity to see and touch that bit/rein device. There is no way in Hades that I would have ever put one of those “war” pieces in any of my horses mouths. Even had I thought about it, my grandfather would have grounded me off his horses until I was an adult, lol
Keep taking lessons and admiring those glamorous fotos. While there’s a lot of good to be said for Some of the “old ways”, that bit & rein set up is not one of them:)
Also, in your foto in post #5, the horse is wearing a snaffle bit::