I don’t see how the benefits of kerning, if any, outweigh the enormous costs.
It also allows letters to crowd each other like friends in a wacky group photo, a tree overhanging a sidewalk, or a cat's tail doing its weird contortions. Fonts are fun.
It’s worth the trouble I think, but there are options if you’d rather not support it.
What I want are two or even three shades for consecutive lines, to make it easier to transition from the end of the current line to the beginning of the next.