The sm coins serve to buy base items upgrade the items that you get in base ascend to epic,legendaries,mythics and divines the coins works to improve your mech but ithink that the coins needs more functions like:
Buy tokens: 1 token=10,000 coins (or 1token=100,coins it have none sense but...)
Buy temporary paints:5 tokens paint=20,00 per day or hour
red paint=50,00 per day
white paint=100,per day
special paints no
Its my idea. is bad people gonna say but is a sugestion