Different games use different colours for the various rarities of item, and I’m sure a lot of people have a particular colour for each rarity they are most familiar with. I thought it might be a nice idea to add the option to change these colours, whether it’s to avoid some people getting confused by which colour = which rarity, or like I said - just to allow people to see things in the colour they prefer. It’s not a big deal, but surely I’m not the only one who would really like something like this in the game.
You may be interested in a mod which does exactly this, allowing you to customize everything or use sensible defaults: