Halter horses are generally just that; used for showing in hand and little else.
Some of them do go on to have performance careers, but like the QH, the Arabian halter horses are not bred for performance anymore, but to look 'pretty' when being show in hand.
I prefer the performance lines, because a horse bred like that can do a variety of disciplines extremely well.
OP, the 'weird gaited' horses you're talking about are Park horses. Arabians aren't truly gaited, but they have a very powerful, floating trot which is exaggerated for the Park classes. Riding a horse like that is like having a freight train between your legs! Not something I've ever aspired to do.
Performance bred Arabs do especially well at endurance and LDRs, because they're hardy and have almost boundless energy. They also bond extremely closely with their rider, which makes communication between horse and rider quite amazing.
I love Arabs. My first horse was an Arabian, as was my heart horse.