There is a fundamental difference between a laser and a concentrated flashlight–lasers are coherent while ordinary light is not and cannot be made so no matter how much you focus it.
Lasers still diffuse; they are not fundamentally different in that sense. In the signaling sense of "is the light there or not?", whether it is coherent, or would be coherent if it was there, is not relevant to anything.
Lasers don't technically "diffuse", they spread out due to diffraction inside the beam itself. So they are much, much easier to better to in a reasonably directed beam.
