Hang Seng have added the China Union Pay logo to their Debit card.

Does anyone know if this is mandatory (no choice in the matter) ?

What are the benefits of CUP ?
It is said that RMB can be withdrawn at CUP ATMs in China. While it is
obvious that extortionate fees (as with credit cards) can be bypassed
this way, does that mean if I have a RMB account with HangSeng, then
the cash gets withdrawn straight from there? Or must it get converted
from the $HK account ?