I didn't mean to dis the devicein the video, just question the stated tolerance. And if the real world tolerance fits my particular practical tolerance needs, then it seems like it could be be useful to make and have at some point.
Unfortuntaely all the practical details are missing -- focusing, or non focusing, safe power level, etc.
In the video, the beam looked quite wide -- but maybe it was purposely non-focused to make filming it possible.
I do realize there also are some tricks that don't actually depend on beam width (like centerng on a round, where symmetry of pattern and/or unbroken vee at the perimeter is what is being looked for) but for simple edge finding, how much can the unaided human eye resolve? Seemed like in printers we used to imagine much over 300 dpi was seen as continuous. That's about 3 thou accuity? Or is there some reason we can distinguish finer with the laser light?
Like I said, I'm not saying it wouldn't be useful a lot of times, but I'd have fairly relaxed expectations of it.