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.
However, even if there are people who are amazed with this kind of modern fireplace, still, there are some who are not impresses enough. Since it uses electricity, you monthly bill can become high. It also cannot produce heat when there is no electricity especially during typhoons when most of the times, there is no electricity.