If the end product ends up marginally cheaper, the company will be able to sell more of it, and this will lead to more profit. And sure, when you ignore the cost of the pollution, this certainly benefits the consumer, by allowing them to afford more energy and energy-based products (i.e., just about everything).

But then we come back to ignoring the cost of the pollution. It certainly gets paid for eventually, but by who? Also, it's cheaper for everyone if the pollution is eliminated to begin with rather than being cleaned up later (which is certainly a more energy intensive endeavor).