> "Who Benefits from Grammarly’s Plagiarism Checker? Whether you’re a student writing an essay, a teacher grading papers, or a writer working on original content for the web, a plagiarism scan will not only save you time, but also help you avoid writing mistakes." ( emphasis mine)
Grammarly Sales has always sold it to academic institutions and teachers, it is must be news to them it is not meant for policing.
The four customers highlighted (Arizona State University, University of Phoenix, California State University, Ashford University ) on the page are all education institutions who most certainly use it for policing.
Also it is product and not feature because it is sold standalone and does not depend on license to their more well known grammar checking product to work.