Nosebands also help the horse focus on accepting the bit. Without one, horses can overwork the bit, gape at the mouth and evade, not accept the bit, etc. Even with good hands… It is an aid. A noseband helps the horse refocus these resistant behaviors. It is not uncommon to see Western horses be argumentative with snaffle contact without a noseband. Most western horses have seemingly quiet mouths because they have much harsher curb bits that the average english horse is not ridden in (who generally has a snaffle).
I use and recommend a crank. People get weird about cranks, but they have the best padding under the jaw and overall comfort. There is no need to “crank” on the crank. I fit mine snugly but not tightly, and my horse can open and gape if he wants to. Leather allows that and there is space in the way the crank fits - the strap doubles back through a loop on itsself.
The flash is common and helps keep the horse from gaping the mouth open. It doesn’t penalize an accepting horse. I rode with flashes until my last mare. The flash irritated her fleshy lips and I just removed it (never had a comment through fourth level shows) and my current gelding also has fleshy lips and is super sensitive so I leave the flash off. He otherwise accepts the bit well. I ride/rode both horses in a very mild Herm Sprenger Training bit, and the mare in a very mild curb with her double. Note that most double bridles have comparatively mild curb bits. I don’t know any Western horse (and I know many ) who go in such mild bits.
If anything, I’d say that dressage riders (I’m a dressage rider) are WAY anal about the comfort of their horse’s face and overall being.