Well, the internet comes through it, so need it for that. Nobody has offered us fibre to the property yet.
We have three storeys, and two mobiles which sometimes struggle for reception at the lowest point of the house, with us at the bottom of a hill.
Having a four-handset cordless phone system allows use to have a phone in most of the convenient locations, without having to keep mobiles to hand, and rely on their reception. They also function as intercoms between the rooms, so if I have the headphones on, and OH wants to attract my attention, the phone will light up on my desk. Communal phone book lives on that, as well.