We have a ton of nylon halters where I work. We have 3 horses that are turned out with halters on. Those three the halters are tied on with a thin leather strip so it breaks if anything happens.
On my personal horse I use a rope halter when training or when she has more than the normal amout of attitude. For bringing in & out of turnout, hand grazing, and trailering it is the nylon one.
Out on the trail I use a biothane halter/bridle combo but usually have a rope one in my bag just in case.
Someday I will have a nice leather one......someday
The love for a horse is just as complicated as the love for another human being...If you never love a horse, you will never understand.