Wood offers a renewable and sovereign source of energy. Wood fuel is available in plenty and there are lower chances you can lack ready wood fuel for sale. As for oil and gas, they are non-renewable so you can expect them to run out any time without prior warning. As for electricity, it is produced by burning fossil fuels which a limited commodity meaning it can run out any fine day.
It does not utilize wood so they are against the environment. Use of an electric fireplace doesn't produce any pollutant or harmful chemicals. There is no release of smoke from this kind of fireplace so there is no need for a chimney or venting system.