I don't recall clearly anymore.
"I think" an "Enterprise" admin can't be opted out of organisation notifications (as opposed to device style notifications) like licence expiry, while a "Full" admin can be.
"I think" this is used with MSP style accounts. The MSP is the "Enterprise" admin, and gets all emails relating to licences, while the customer is the "Full" admin and gets everything but the licence notifications.
My memory is pretty shaky on this one.