Everything that cowboys wore had a purpose, and was designed with safety in mind because their job was their life! (As my trainer used to say, If a cowboy in the 1880s had had a helmet to wear, he would’ve worn it! Everything they used was designed with safety in mind! But that’s a topic for a different thread.)
Perhaps this is not historically accurate, but it’s picked up from many many old cowmen and outfitters whose horses are their lives. Here’s my impression of WHY cowboy boots are the way they are:
Pointy vs square: Square is a new fashion look, and offers more comfort for the toes or wider feet. Pointy boots might not have been as comfortable to walk in, but no self-respecting cowboy walked! Also, pointy toes are much easier to pick up a lost stirrup with while you’re running at breakneck speed.
Short vs tall: Short boots are solely for fashion. Short boots didn’t evolve until the 1960s, I believe, and that was simply to save money on leather for people wearing cowboy boots while not riding horses. The tall shaft protects your legs from brush, horns, barbed wire, rope burns, stabby branches, etc. For a lot of people, 16" tall-tops are a mark of pride, and they wouldn’t be caught dead in anything shorter.
Jeans in or jeans out: This fashion started in the 1800s with guys wearing long pants cuffed over their boots. Boots at first had quite plain stitching. Later, it evolved to wearing jeans inside their boots: cowboys’ tack was a huge source of pride, and owning a beautiful pair of custom embroidered boots was reason for bragging rights, so jeans got tucked in. Personally, I do it for practicality as much as fashion: I CANNOT STAND the feeling of my jeans inside my boots, because while riding a big circle jeans always tend to creep up your calves. I hate that. I absolutely wear tight-legged jeans inside my boots for comfort sake.
Leather sole vs crepe vs rubber: The slick leather sole had a purpose: not only did it provide better feel on leather stirrups, but it also slipped right out in an emergency. Remember, cowboys didn’t walk in their boots, so there was no need to worry about the ground! I, too, find too-slick leather soles kind of dangerous on grassy slopes. Even scuffing them isn’t good enough for me, so when I get them re-soled, I go with a thin, treadless rubber sole. I don’t like crepe soles: they look thick and chunky, they feel thick and chunky, and they stick to stirrups. Dangerous! Plus, crepe soles seem to wear out a lot faster.
Chinks, armitas or chaps: This seems to be a matter of personal preference. I almost always wear my chinks, unless I’m riding a green colt (then I wear my favorite suede chaps because they stick to the saddle). Chinks, armitas and chaps all evolved to protect a rider from rope burns, horns, branch stubs, etc. while working. If you’re a brush popper or a cowpuncher at altitude, or an outfitter anywhere, you definitely need them. Otherwise, I think it’s all about your preference/the region you live and work in!
Someone mentioned heels and the hard leather toe, as well. Heel height should be around 2-2 1/2 inches (traditionally), and well-sloped. None of those straight heels they sell so often. Surely I have read of a purpose for this, but I can’t remember it right now The toe should be rounded, hard leather, not soft at all, to protect from all kinds of nasty things that can happen to your feet. Cowboys often wore their boots one size too large, and with a solid steel shaft, to offer a great stiffness and an easy boot to slip off, in case they were hung up in their rope or stirrup.
If you find a boot that meets all these qualifications, it will invariably have a beautiful little spur shelf on the back of the heel, where your spur will rest daintily. A custom-tooled pair of spur straps was a must. The wider ones seem to support my spurs better than the narrow ones. (While no one asked my opinion, I have to offer that Olathe boots are my personal favorite.)
Having used cowboy boots for years as an essential part of my working gear, I have found that most of the “old” reasons that boots were made the way they were are totally valid. However, if your job doesn’t involve punching cows or riding herd on a bunch of dudes, then I think you’re safe letting fashion be your guide.