At one job I had, I happened to have gotten a promo code for a specific game that I didn’t like but I thought my boss might enjoy. So I handed it off to him. It then became a thing for him that he played pretty regularly for a couple of years, which surprised me. He never would have tried the game without the promo code, and I’m pretty sure he spent some actual money on the game even afterwards, which makes that a successful promo. Can’t get much more than that!
But then, some people are not enticed by that at all. I am always up for a free thing in a game I already play, but if you try to entice me to play your game by offering me a free whatever, I am more likely than not just going to ignore the game. So has a free gift ever enticed you to play an MMO? Have you ever started a game because a cross-promotion got you a new cosmetic outfit or something, or is that just not the way you are going to play a game?