As a quick note, if you have a 4K HDR TV and use a Windows 10 computer on it, disable HDR in the display settings. Leaving it on will just cause your picture to look awful (drained of color, dim, etc.). I couldn't figure out why my picture looked so bad on my HTPC, but once I turned that option off, it went back to looking like normal. To my knowledge, turning off Windows's setting will not affect any game or full-screen/exclusive mode application that uses HDR.
Unless h.265 is eight times more efficient at compressing raw video then I will continue to keep my reservations. Not knocking what Netflix is doing because the average cowsumer sits too far from their 4K display to even benefit from the increased pixel resolution. Sure, they'll get a benefit of other things like a wide color gamut, but as for resolution and compression Netflix is catering to the ignorant cow on its books.
As a side comparison, I've watched 4K content from YouTube on a 4K TV, and it looks fine. Would it be as good as a UHD Blu-ray? No, but it doesn't look bad at to me. Honestly, I'd care more about HDR/Dolby Vision or Dolby Atmos than I would simply getting 4K. Although, keep in mind that using streaming apps directly on the TV will not allow you to use fancy audio modes as HDMI's ARC will not support object-based sound files (Dolby Atmos, DTS:X) until HDMI 2.1 and S/PDIF only supports lossy formats. So, you'll want a secondary player, and as I mentioned earlier, secondary players may not support 4K settings out of the box on certain video apps. (It's a pretty big mess.)
EDIT: As a quick note, YouTube uses VP9 not h.265.