If you asked me to pick out bright bold blue (#0000FF) and told me the format was "Lightness Chroma Hue" with valid ranges, I would guess "0.5 1.0 240". Not only is this "not visible on any monitor" by a very large margin but the oklch.com calculator states the spec fallback color is Dell logo blue and not bright at all while browsers will render "vibrant purple".

There's not "120 degrees of red, 120 degrees of green, 120 degrees of blue", so blue is not 240. Actual bright blue is hue 264. The "0-255 RGB" bright blue is 0.452 lightness, and max chroma on a really good monitor is something like 0.33. The lightness mostly makes sense, right? 0.5 is halfway between totally dark and completely washed out.

"Ok, so chroma tops at at 0.33" not so fast. You can crank up the chroma to 0.40 and still get either magenta (where lightness is around 0.74) or green (lightness around 0.78). So now you need to know a valid, nonlinear lightness range for each band of colors, because midpoint blue is different than midpoint red which is different from midpoint green.

From greyscale luminosity calculations and knowing about subpixels and bayer filters, I would've been able to guess that green is the color with the highest chroma, but then there's bright magenta, neck-and-neck. Oh. Until I move the lightness slider down on the web color picker, and then everything (especially peaks) in the chroma channel shifts around dramatically... So much for intuition.

While OKLCH makes it really convenient to select colors with properties you like along a gradient, the nonlinearity means either memorizing a bunch of base colors, using a color picker, or converting from a system that is "actually" intuitive. I can't really look at a trio of OKLCH numbers and predict the output color like I'd be able to with RGB, although this is mindful that RGB is also not linear (for the exact opposite reason as OKLCH) and I can only do that from decades of experience.

I'll concede that magenta and bright green and bold blue don't really have a place on the world wide web other than in a company logo, so these are outliers. Still, the OKLCH format is not what I'd call intuitive to a total beginner.

(Also, I'd very much not like to implement OKLCH calculations on a microcontroller until lighting companies start selling OKLCH LEDs.)

bro what?