POC representation

[Enla]

I grew up watching Inu Yasha, where most characters did have Black hair and dark eyes (minus the demons), and you could tell the characters apart, so it can be done, but for some reason most anime don't do it.

Part of it is a borrowed issue from adapting from manga. Having different colored hair + widely different silhouettes makes it easier to tell characters apart when it's just black and white ink. Plus it gives an interesting little color 'punch' when the mangakaka is allowed to do a color spread. The other part is partially style laziness. You'll notice a lot of anime have characters with same face+hair syndrome, A1 Pictures is a huge offender with their titles, so the addition of colors is there to help you tell who is who at a single glance without confusion. Stuff like Satoshi Kon's Paranoia Agent where everyone has a unique body shape + face on top of having black hair + black eyes is pretty rare in the industry outside of film.