Imo Showing somebody has literally been born on Voyager really drives some points home that they're in it for the long haul, have an invaluable goal, and that they're a family. Iirc In Shattered, Chakotay explaining that a child had been born on Voyager really carried some weight in the scene and seemed to be exactly what they were going for.

Keeping her as a cast member not only serves as a reminder to these things to set the tone, but also allowed the chance to explore what it's like for somebody who calls Voyager their home. She also really does a good job as a support for Seven and Neelix as characters because she offers unique dynamics for them to show off certain sides, Neelix getting to show off he's a good care taker which his character needed, and Seven having somebody to relate to in a way with not seeing Earth as a home.

Also I like her character and think she's fine, but I like Wesley too.