It does not cause crosstalk, which is a critical limiting factor for twisted pair cable. What's more, it can be run in electrically noisy environments, such as a factory floor, without concern since electrical noise will not affect fiber. There's no concern with proximity to noise sources like power lines or fluorescent lights. In short, fiber is inherently more reliable than copper. Fiber optic cable weighs less than comparable copper cable.
Lighter weight makes fiber easier to install.
Fiber optic cable has a smaller cross section than the copper cables it replaces. Since the fiber is a dielectric, it does not present a spark hazard. What's more, cables are available with the same flammability ratings as copper counterparts to meet code requirements in buildings. Optical fibers are quite difficult to tap. Since they do not radiate electromagnetic energy, emissions cannot be intercepted.