Fun Fact: Gacha Life allowed you to do this! (I'm not sure if you can still color face shadows in gacha life, or if this was removed in updates for the same reason it's not included in gacha club.)
The reason Lunime removed it for Gacha Club was because people making gacha heat kept using pink and red face shadows, which is unfortunate as it was quite versatile.
also because we were forced to rely more on facial expressions than before since pretty much everyone at the time used green face shadows to communicate a character being disgusted or ill.
Just a bit of gacha history!