We actually bought a dryer recently because it was more energy efficient than hanging the laundry in our house. I know, I know. It doesn't make sense!
But, if you live in a house in Scotland that doesn't have central heating, and you have to use electric oil-filled heaters to heat the house and dry the clothes, it costs an absolute fortune. We always had to have a heater on because there is always laundry to be done, and otherwise it would take days to dry. Even in the summer on rainy days, we'd have to put a heater on!
Our new dryer uses 1/4 of the energy of the heater, dries my clothes to fluffy perfection in 70 minutes, and also warms up the living room in which we keep it. It's noisy, and ugly, and in the way, but I wouldn't trade it for anything!