Your benefits from registering KBACKUP(either by sending money or, for private use, with a postcard) are that you will receive information about further development and bugfixes. The author will also try to give you as much support as possible.
It will also keep me motivated to continue this work, which takes an awful lot of time and energy. So, if you use KBACKUP, please register, either with a postcard or, if you use it commercially, by paying the registration fee. For details see the Appendix B.