"we finally explain what HDR actually means"
Then spends 2/3rds of the article on a tone mapping expedition, only to not address the elephant in the room, that is the almost complete absence of predictable color management in consumer-grade digital environments.
UIs are hardly ever tested in HDR: I don't want my subtitles to burn out my eyes in actual HDR display.
It is here, where you, the consumer, are as vulnerable to light in a proper dark environment for movie watching, as when raising the window curtains on a bright summer morning. (That brightness abuse by content is actually discussed here)
Dolby Vision and Apple have the lead here as a closed platforms, on the web it's simply not predictably possible yet.
Best hope is the efforts of the Color on the Web Community Group from my impression.