Over the 20th century, people switched from fuel based lighting, heating and cooking to electric, and acquired laundry machines, dishwashers, fridges, TVs, air conditioning etc etc. So electricity was a pretty good proxy for a certain aspect of quality of life. It might be a less useful measure in the developed world in the 21st century as we have kind of plateaued on energy-intensive appliances and are more focused on efficiency, and because other aspects of quality of life like pollution, work, mental health etc may be more salient.