I am getting better picture quality by using 1080p with HDMI 2.0 cable in my 4K UHD 55 " TV...In India, all channels broadcast interlaced format. Even when I compared 1080p and 1080i on my hevc hd box, I found 1080i video quality better than 1080p.
If you are watching a sports channel and select progressive(1080p) the moving objects look blurred. Whereas, in interlaced(1080i) the moving objects are more defined and picture quality is also sharper.