Unless your prowler is dense enough to walk right into your light, you will not be able to get a good look through the glare. With the light not shining directly into the eyes, the fixture does not blind the person. The eyes adjust to extreme contrast better if the illuminated area is the only thing the light is shining on. Esthetically speaking, shotgun lighting destroys the beauty of the night sky, making observing and astrophotography difficult, if not impossible. Light pollution literally drowns out the dimmer stars and objects, like the Milky Way, Andromeda Galaxy, Lagoon Nebula in Saggitarius, the great Globular Cluster in Hercules, the Beehive open star cluster in Cancer, and many others too numerous to list.
Light pollution leaves only the moon, planets and brightest of stars visible to the naked eye.
There are many more treasures of the night sky that light pollution erases. Long before television, radio, motion pictures, and the electric light, people entertained themselves by drawing pictures in the sky. With their imaginations, people created pictures of their favorite characters, and told stories about them. These legends survived down through the ages. It's a shame that from my backyard, on an average evening in Columbus, I can barely make out the constellation Hercules to show my children.