Before using NoiseChisel it is strongly recommended to read Akhlaghi and Ichikawa  to gain a good understanding of what it does and how each parameter influences the output. Thanks to that paper, there is no more need to continue this introduction any further and we can just dive into the details of running NoiseChisel in Invoking NoiseChisel. However, the paper cannot undergo any further updates, but NoiseChisel will evolve: better algorithms or steps will be found, thus options will be added or removed. So this book is the final and definitive guide. To make the transition form the paper to this book easier (and encourage reading the paper), below you can see the major changes since that paper was published.
This will improve purity and not change completeness (a true detection will not be discarded). Because a true detection has flux in its vicinity and dilation will catch more of that flux and increase the S/N. So on a true detection, the final S/N cannot be less than pseudo-detections.
However, in many real images bad processing creates artifacts that cannot be accurately removed by the Sky subtraction. In such cases, this option will decrease the completeness (will artificially discard true detections). So this feature is not default and should to be explicitly called when you know the noise is clean.
For a more detailed list of updates in each release, please follow the NEWS file. The NEWS file is in the released Gnuastro tarball (see Release tarball). You can also see it online at http://git.savannah.gnu.org/cgit/gnuastro.git/plain/NEWS.