Topic: Word clock

Looking to purchase raydat pcie card and run it with an octamic ii, and a steinberg MR816, both via adat (possibly a 3rd channel strip in future). The last adat port on the raydat will be used for cubase system link.

What exactly does the rme hdspe word clock expansion card offer (WCM), and would it be of benefit to me in my set up? As you can tell, I'm new to the concept of wordclock.

Thanks in advance for your help.