A dark-sky compliant fixture can save you money. By casting light downward only, dark sky fixtures provide just the right amount of light exactly where needed.
We benefit from using dark sky compliant fixtures because people can see the stars, we use less energy, and we reduce the effects of unnatural lighting on nocturnal animals. So do a favor for your local astronomer, turtle or owl and consider going to the dark (sky) side.
Dark-sky compliant outdoor light fixtures are designed to reduce "nocturnal glow & glare" from urban & coastal areas.