The tool in question is used a great deal by those with training and experience with it.
As many who have trained with flexible tools can confess.. they can be very fun and a puzzle to master.
I have 4 levels of weaponry ranking in my System and the kusarifundo is covered is that section.
Also in that section I have the kusarigama with the kusarifundo.
The major problem I found in the Bujinkan was that this tool had no outline or path persay. To solve this I worked out a outline.. it took 5 years to get it done.
I have a complete outline with the kusarifundo that can be seen on the Houston seminar of 2/2002.. well some of it can be seen.
The outline covers standing, kneeling and ground combative skills.
kamiyama, ralph severe