On one hand, it's better if we get rid of coal than if we don't, and we should do it now.
On the other hand, people who work at coal plants and lose their jobs will not turn around and become solar panel installers or wind turbine maintenance technicians. The most likely outcome is life will get worse for them. We've seen the consequences of this already from the manufacturing sector, and it's not pretty. Drugs, poverty, violence, depression.
I'm not saying we should not close down coal plants, I'm just saying there will be consequences and "they'll all work for clean tech, and live happily ever after" is not a responsible plan.