The purpose for a compass is to help navigate forward, and it serves as a mooring presence reminding Olivia that her and Elliot are on a path that leads to happiness. This isn't an ending, but rather a start to something great.
"I don't know. Maybe I just wanted to hear your voice."
The fact that she's the first person he calls. Despite the apprehension, he calls. When he starts to make an excuse, he catches himself and admits that he just wants to hear her voice. Oh, how the times have changed. This is growth. This is what Liv has needed from him.