You still think an estate is needed when having a child?
It makes life easier. But with the roofbox for longer stays away it's fine.
I just did a week in the lakes with a 12 week old, so every kind of baby paraphernalia you can need (Moses basket, stand, buggy, steriliser, bottles, milk bla bla bla). Then all the wife's "stuff" and walking boots, hiking clothes etc. Wouldn't have been viable in the 3'er without the roof box.
Most of the time though a saloon is more than upto the job. And the older they get, the less stuff they need so as time goes on the roofbox may become redundant.