Only comment I have on this is that you don't have to do heroics to get coins. You don't even earn most coins that way although technically you can. You get tons of coins from engrams, and by doing public events, turning in faction packages, and playing normal crucible. All things which happen over the course of the game. So even by buying it you didn't really "earn" it beyond RNG giving you coins as you play. Heroic is the only surefire way to get coins, but I get more just from playing the game in a week than from doing those strikes.