You can adjust the flames, and they don't waste heat the way the older models did by trapping it inside, or the way wood-burning fireplaces do by letting most of it escape out the chimney or flue. Contemporary fireplaces demonstrations that something pretty can be completely practical. And convenient. There are no ashes or dead embers to clean out regularly, and there is no need to be able to light a fire with newspaper. If you already have a wood burner, you can get a new gas insert to convert that old fireplace into a better fireplace.
Aside from keeping the warm air from escaping, the doors act to keep the hearth clean just as a fireplace screen used to do in the olden days. With the doors closed, ashes and embers don't scatter about the room, keeping the carpet or rug clean and scorch-free. The doors also have built in devices that divert air towards the bottom of the fireplace. These vents make the fire burn brighter and easier to light.