This is in no way a gray area. You're trading game gold for game services. Unless you start receiving compensation outside of the game for carry runs, you are 100% safe.
As someone who has literally no interest in grinding out the endgame content, and just wants to pick flowers and breed chocobos and decorate houses, I STRONGLY appreciate the carry runs as an option~~ ヽ(*≧ω≦)ﾉ