How does publish_form_headers differ from show_full_control_panel_end?

I’m having a wonderful time writing a neat extension tonight, but need to know the difference between two hooks:

publish_form_headers Adds content to headers for Publish page

show_full_control_panel_end - Rewrite CP’s HTML - Find/Replace Stuff, etc.

I assume publish_form_headers will only add stuff if I’m on the Publish page and no other? Seems like show_full_control_panel_end is commonly used for adding all sorts of things - including JavaScript and extra CSS.

Is it best practice to use show_full_control_panel_end for ading JS and CSS? Is there a more appropriate hook for adding things to the header of the Control Panel?