I used some CNB pts to book an AS airfare through their portal. The X fare cost $25 more via their portal than booking directly with the carrier. There was a small cash copay (I didn't have enough pts) and that coded up as MCC 4722, which is Travel Agent & Tour Operators. I could have saved myself that fare differential by calling into the concierge and booking over the phone, but given all the troubles I've generally had with that (with other firms, not CNB explicitly) I'd rather not take the risk of getting names, KTN, FF, or anything else wrong. Fixing those the next day after ticketing is annoying. (And the fare went up $50 this morning too!) Redemption value was ~1.18 cpp
One other thing, which I've had with other OTAs, even though my AS FF is attached to the ticket, is those bookings never seem to autopopulate on my AS account under MyTrips. And CNB's Connexions website doesn't send email confirms of booking even though they state will. I've had that problem with Connexions at Citi, Chase, and others. It's not a spam folder thing either.