Some of plugins were written with user friendly policy in a mind and has an option at their settings to hide selected widget. What to do with plugin which does not allow blog owner to manage what widget to show at the WordPress back-end dashboard and what does not?
Yes, any user may hide unneeded widget switching of correspondent checkbox inside the “Screen Options” at the top of the page. But suppose, that You, as administrator, wish to make your blog dashboard more user friendly and to help your users to spend their time more effectively. Some times you even do not wish to let user know, that some widget is available at all. Use this recipe to make your dashboard cleaner.