If you could remove a gigaton of usable coal from the world and replace it with an equivalent amount of natural gas, that would be a nice improvement.

When the natural gas is displacing coal by being cheaper, that's pretty bad in the long run. We're still probably going to use that coal later, and cheaper fossil fuels reduce the price pressure to install renewables.

> and can be burned in the same power plants

I don't believe nat gas is burned in the same plants as coal.