Henry -- I don't know of any laptop that allows you to connect its internal Displayport-connected display to the laptop's HDMI output port. Yes, there's options for external displays but I don't carry those around with my laptop and don't sit one on my lap with the laptop when I'm using my laptop in bed or on the couch.
Yeah, exactly.
Of course we'd use something other than DisplayPort to get around this problem if we could. Also, changing inputs every time you want to use WMC (if you have a G-Sync monitor connected with DisplayPort), is a pain in the ****. That's not a solution, it's a bandaid.