Seems kinda like an impractical version of augmented reality glasses. Even if they can shrink down the projector/camera size, there's still the issue of batterys, which haven't shown much progress in the way of shrinking.
Projecting an image onto glasses won't be nearly as power hungry as a full-on projector.
Instead of being a personal device, shoulder-mounted device, I could see this being useful for industrial applications, serving as a guide to workers piecing things together.