They click because they have more points of engagement? I'm probably 100% wrong there, but hey. It's not a DH/FR thing, it's dependent on the hub.
I hate loud hubs.
Ya, trials and bmx riders have some loud hubs too
I know I have one hub, unknown maker from a downhill bike. Shiny and new (basically), more silent than anything I have heard. Someday I will build a wheel around it.