Example 1: This plugin works particularly well with scanned logos. This proves to be useful, if you wish to reproduce a logo for a website. Compare the result with a normal threshold ...

Example 2: This plugin allows to get interesting shapes. From left to right : we took an ordinary shape, applied some gaussian blur, and finally used effect Fine Threshold.

Remarks:
Quality of the result depends of the image. The plugin Fine Threshold doesnt like noize, posterization of levels (revealed by regular histogram gaps), extremly smooth transitions (case of big gradients).
Avoid excessive values for the threshold (near 0 or near 255).