I noticed that the missions reward a differently-colored coin (I can't remember which color, but I think it was green or blue) and I don't know what to use them for...

this thing?
The "Faction Reward" is the same as Reputation, I do believe, just under another name- that is, as you get more, your reputation ranks up and you can access more items at the city's shops and harder mission difficulties

(to clarify, it's basically what you could call "city exp", used for leveling up your reputation with them, not a currency that you can spend)

Link: https://www.sylestia.com/forums/?thread=86680&page=1#2 Author: Scathreoite Time Posted: 3/3/2020 at 10:14 PM this thing? The "Faction Reward" is the same as Reputation, I do believe, just under another name- that is, as you get more, your reputation ranks up and you can access more items at the city's shops and harder mission difficulties (to clarify, it's basically what you could call "city exp", used for leveling up your reputation with them, not a currency that you can spend)

Thank you so much!