All that little snippet does is hide the small action posts for everyone, and then make them visible to staff users. To be honest, I find the small action posts quite useful (especially the ‘closed’ one), so I wouldn’t advocate hiding them - though deleting some can help clear some noise.
Staff users get a ‘staff’ class added to the page when viewing, so it’s easier to target them. If you wanted to add others I think that would require something more complicated. There’s an example of how to add a specific ‘admin’ class in this post which you may be able to adapt?