Just checking in to let you know that this plugin is fantastic. The previous one in paint.net was getting frustrating because it would show horizontal banding artifacts. (I don't know if it was the included or one I added to Effects.) This one does not show those problems at all!
As to the modern uses - although not my day job (or paid job :-( ) I sometimes have to prep items for commercial printing. This plugin is ideal for reducing grey scale images to dithered black and white, which give much more predictable results at the print shop. On a similar note, it is ideal for building index
