One reason to care is when designing applications that work well for all users. In particular, I've noticed that in recent years there's been a trend of colouri

One reason to care is when designing applications that work well for all users. In particular, I've noticed that in recent years there's been a trend of colourizing CLI tools, often assuming a black/dark background. So now your CLI tools emits yellow text on my white background, and the first thing I have to do is figure out how to fix or turn off these darn colours. In some tools it's non-trivial to do so.