I have a firend who never had a car or license, but she had a seat JIC.
& til you have a baby you have no idea just how many times you will use it.
Middle of the night trips to the hospital, quick trip to the shops for baby panadol for a screaming baby when on your own, visiting friends/family or vacations.
It may not be necessary, but it will be handy. Even if you do get rid of the car, you never know when you might decide to go for a day trip or something in a friends car.