It was more for an FX addition to the viewfinder screen. To show that he is indeed looking at an image as the Range Finder is down. As it stands currently in the scene, it really isn't clear enough to see anything but a white light.
I thought showing what he is looking at (which looks like a scene from Lawrence of Arabia), would imply that the original thought was Boba Fett looking at a small view screen with a display.