Lens hoods are primarily designed to prevent unwanted stray light from entering the lens by extending and shading the end of the lens. In addition, since the end of the lens is extended, you also get the added benefit of some extra protection from accidental impact. Dedicated lens hoods are designed to match the specific focal length of the lens it was designed for.
Cost-wise hood that works. Fit well on lens Canon EF-S 18-200 mm. The bayonet model allows for a quick removal and reversal of the hood for simpler storage. As others have mentioned there is no "red dot" to help you align it with the "fat" flaps on the top and bottom. However is a not brainier to lock in place so this is hardly a problem.