There are three ways to control Safari's Website Preferences…
  1. The Develop Menu
  2. Website Preferences icon
  3. Safari Preferences > Website

They are all control the same Safari API and have the same scope of effect. If you change one that change will appear in both of the others. The advantage of using the website preferences icon is it automatically forces the page to reload.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein