OA publishing allows work to be widely discovered, freely read, and frequently cited. OA is fully compatible with peer review; though some OA journals are not peer reviewed.
OA may reduce library costs by eliminating excessive subscription fees to boost publisher profit margins, but OA is not free (costs to run peer review, editing, distribution must be covered).
Following are a few articles that advocate for Open Access. See the Further Reading section for others.
What Do the Authors of Sci-Hub’s Most-Downloaded Articles Think About Sci-Hub? Chronicle.com (5/13/16).
Elsevier Denies it Will Force SSRN Users on to Other Services. The Times Higher Education (5/19/2016).
Who's Downloading Pirated Papers? Everyone! Science (4/28/2016).
Academics Want You to Read Their Work for Free. The Atlantic (1/26/2016).