In my humble perspective, more history and context would be required to attempt to accurately guess upon what you are asking. I am not requesting you to share any more than to which you are choosing.

Since you asked, "Do you think she just did that out of obligation or is playing mind games or something," there seem to be multiple possibilities that consist of motives, objectives or lack there of (motive and/or objective.) She could be bored, lonely, lining you up for future "use," guilty, remorseful, change of perspective and/or behavior, misses you, misses you and is embarrassed of her past actions of leaving the relationship/friendship she did to name a few explanations.

With that said, from what you state and how you convey what you state, self-interest seems like a probability to how much ever of a degree as to why she is contacting you now (and in the past.)