It’s fine for softies and some LPS that’s mounted a little higher in the tank but I wouldn’t recommend it for SPS. I kept corals alive and growing for over 2 years using the Orbit Marine fixture.
Fish don't really need light. It is basically just for us to see them. Some corals need light some don't, NPS for example. At 36" that light won't be beneficial at that depth for much, if anything, except fish. But like others have said, it will work for things higher up in the tank.