Object-oriented ontology is not just a technical metaphysical position with no downstream consequences. Its practitioners, and a significant number of people in adjacent fields who have found it useful, argue that it changes how you think about art, ecology, technology, and politics.
Start with aesthetics. Harman argues that art is the central discipline for OOO because art is uniquely concerned with the gap between an object and its sensual appearance, with making you encounter the real depth of a thing rather than just processing its practical profile. When you read a great novel, you do not get a set of propositions. You encounter a world, a complex object, that exceeds any paraphrase of it. This is why paraphrase kills art: the novel is not a delivery mechanism for its themes; it is an object whose full being is present only in the experience of it. Harman's OOO account of aesthetics resonates with why people feel that certain artworks are more than the sum of their descriptive content.
In environmental philosophy, OOO's insistence on the reality and importance of non-human objects has been influential. The philosopher Timothy Morton, a collaborator and fellow-traveler of Harman's, has used OOO-adjacent ideas to develop the concept of dark ecology: an account of ecological thinking that resists the nostalgic narrative of nature as a pristine, harmonious background to human disturbance. On Morton's view, "Nature" (capital N, as a unified harmonious whole) is a philosophical fiction that actually impedes ecological thinking. What we have instead are objects, organisms, ecosystems, geological formations, with their own being, their own histories, their own irreducible reality. Ecological ethics should respond to these actual objects, not to an idealized Nature.
The broader political and ethical implication is sometimes called flat ontology: the claim that there is no ontological hierarchy in which humans are uniquely important and everything else is merely a resource or backdrop. A coral reef is as real as a corporation. A virus is as real as the human it infects. This does not mean humans and coral reefs have the same moral status, that is an ethical question that flat ontology alone cannot answer. But it means that the reflexive assumption that reality is organized around human concerns and human perspectives is a philosophical choice, not a metaphysical discovery.
The criticisms of OOO are also worth taking seriously. Some philosophers, like Peter Wolfendale in Object-Oriented Philosophy: The Noumenon's New Clothes, argue that Harman's framework is philosophically empty: the withdrawn real object is by definition inaccessible. Means the claim that it exists cannot be tested, criticized, or developed. It is a black box at the center of the theory. Others in the speculative realism movement, particularly Meillassoux, disagree with Harman's approach while sharing the broader rejection of correlationism. And many analytic metaphysicians simply find OOO's arguments obscure and its conclusions underargued.
The fair assessment: OOO is a genuinely interesting and provocative philosophical position that has been unusually productive, it has generated new thinking in aesthetics, environmental philosophy, media theory, and architectural theory. Whether its central metaphysical claims hold up under rigorous scrutiny is a live question.