The public distribution list builder is already installed on their system I believe - if I remember correctly that tool was introduced back in 4.0(1) builds. The version on the www.CiscoUnityTools.com site is newer, of course, so you'd want to update anyway.
Either way, the tools are independant of Unity and will not cause any problems with it - yes, you can uninstall them if you choose to but there is no legitimate reason to do so as there is no possibility of it interfering with Unity's function.