Yes but given that that is the case (player not supposed to know that she dies), they wouldn't necessarily level her up to get all 4 limit break levels and most likely -wouldn't- use her in the main group unless they had to just because healing is pretty much all she's good for.

And yes, I do think that if someone were to go into this game with no clue as to what the story line is or a walkthrough to help them, they wouldn't necessarily use Aeris.