This isn't even sad, this is actually more of a bittersweet happy. The worst thing about someone you know abruptly dying is the regret of never being able to tell them exactly how you feel. From personal experience, I had an uncle who killed himself after an argument with his wife, and I'm sure she wished for a long time she could tell him how much he really meant to her. But you can't, there's no way to talk to the dead.
This is kind of the fulfilment of this wish. Much as the dead girl wished she could apologize to her grandmother for breaking her photo, MC wished she could tell dead girl she loved her and get some kind of answer. And she does! She gets to get those emotions off her chest and achieve closure with her emotions. If only we could all talk to ghosts...