Here's a video showing off how and when to use it (thanks to Matias for letting me use the file from the blog for testing :)
From the video description and commit log:
This operator helps fix up this mess by taking the selected strokes, projecting them to screenspace (i.e. "flattening" the strokes back on to the screen), and then putting them back out into 3D space again. As a result, it should be as if you had directly drawn the whole thing again, from the current viewpoint, but without losing the pressure/strength info.
Unfortunately, if there was originally some depth information present (i.e. you already started reshaping the sketch in 3D), then that will get lost during this process. But so far, my tests indicate that this seems to work well enough.