The RAISE act is likely one of the most consequential pieces of environmental legislation to be introduced into congress in years. How is that you ask? 
Most of the US's population growth in the last few years comes from immigration (88% in the last few years according to Pew). A growing population means more consumption of resources (gasoline, land, water, etc.) and thus more impact to the environment. And a growing population makes attaining sustainability goals impossible.
By limiting immigration we are greatly reducing our population rate of growth which is a plus for the environment and sustainability. Besides, it's also a quality of life issue too. Do we want to be as overpopulated as China or India? Growing our population by 30 million every decade may be good for business but is terrible for everyday Americans, environmental quality and our quality of life.