TL;DR Nearly 50% of HWB possible values tends to grey shades.

In both HWB & HSL colors, we can describe white and black and a full scale of grays using any hue we want. It doesn’t matter what hue we provide in either table

Lucky for us, browsers don’t generally render gradients using naive HSL math: currently browsers convert everything to sRGB before mixing. Gradients in RGB can still get muddy at times