I agree, for the cost of adding an HDMI input, it would be silly to abandon the P3/P4 installed user base. I get it that DJI is making Occusync its video connection technology. Depending on cost compared to, say, Fat Shark, I'd consider a pair of DJI Goggles because it's likely that my next drone, Mavic or Phantom, will have Occusync. And, I suppose Occusync will be proprietary, so Fat Shark and the others won't be able to use it. But HDMI is pretty good, so if the DJI Goggles are too expensive, I'd just go the HeadPlay or FatShark route for HDMI rather than paying for Occusync capability that I don't really need right now.