Great article, as always! Very informative 
I personally never used HSL values for colors, but instead always gone with either HEX or RGB. Then again, to be fair, I mostly use tools to get the color I want (like, for example, the W3Schools color picker, or even the built-in pickers that some code editors have - I use VS Code, don’t know about the others) 
After reading this, however, I really have a feeling that HSL is much more intuitive than other systems, so it is surprising that it’s not used more often. Although, it might be because people are already used to representing colors with the RGB model. I guess breaking a habit is never easy, even if it makes your life easier (plus, as you’ve mentioned, there’s the issue of compatibility with older browsers) 