The Verge's Nilay Patel:
The move is said to be "largely symbolic," as Netflix still owns whichever discs it purchased previously and can still legally purchase future HBO discs from other parties and rent them to customers under the copyright doctrine of first sale. (Indeed, Netflix says it will continue to offer HBO DVDs and Blu-rays, although it's never had any HBO content on its streaming service.)
Netflix will now be in direct competition with HBO when it starts airing its self-published shows. This kind of thing reminds me how bad it is for the consumer when content providers and delivery channels are the same entity.
This reminds me of EA and Valve having a spat over EA's games in the Steam store only after EA opened its own Origin store. It's interesting that my gut is to give Valve a pass on their integration but having a bad feeling about Netflix producing their own content. Maybe it's because Steam has already become the defacto PC store and is free to access (you only pay for the games you want to have on it, not a monthly fee), while anyone wanting to watch Netflix produced "television" who doesn't already have an account will have to sign up for a paid service they don't already have.
That might not be it, though. I'll have to ponder.