It looks like it’s used more for surface finishing than removing gross amounts of material. Like for clenaing up castings. http://www.extrudehone.com/auto/auto-performance.php Or after the main porting is complete, this may get you that extra few percent. I haven’t actually seen numbers though, so this is just guessing on my part. Of course, if you can’t get to an area to port by hand/machine, then this process is an alternative.
But yeah, I think we’re getting into nitpicking of what words mean.