There are more reasons as well. If she is younger than you, it can screw up things in ten years if you decide you need a reverse mortgage for whatever purpose. It's also disadvantageous to her, if the goal is for her to have it when you die. If you give it to her now, she gets your basis on the half you give her now rather than it stepping up on your death.
Being on the deed isn't like some club membership, it means you are giving away half of the house to the other person.