That’s a PC Gamer article for gamers written by a games journalist, horrible source for anything actually technical. UE4 has always assumed you are using physics-based materials, so there’s no extra work needing to be done from the artist’s perspective. HDR assets isn’t a thing, PBR assets is. 16 bit color is nice for certain textures, where variation is very subtle, and normal maps, but it is absolutely not a requirement for HDR.
The biggest thing really to making sure your game is taking full advantage of an HDR display is to test early, use real world values as reference as much as possible, and pay attention to your lighting and post processing.