Asking whether a Audi A4 B9 Avant 45 TDI quattro tiptronic is a useful automobile for families, is not easy to answer from a technical point of view. families pay attention to a wide range of things when buying a new Automobiles, so this consideration only considers the common aspects.
The Audi A4 has 5 seats, which is enough for many families, and also brings a decent trunk with 1495 liters of volume, in which there is still room for luggage even with a stroller loaded. Good conditions for a family car. There are no Isofix brackets installed. These could be used to secure child seats easily and safely.