For example, a Page manager might have full control while a Moderator may only be permitted to respond to questions and comments. This allows for better management of your Facebook Page and provides more opportunities for staff and external businesses (e.g., to measure analytics) to access specific features of your Page but only those relevant to their jobs.
There are five distinct roles: Manager, Content Creator, Moderator, Advertiser, and Insights Analyst. I include a table (sourced from Facebook) that illustrates what kinds of actions these different roles can perform.
Clearly, the Manager role has the most permissions (which matches responsibility level) while the Insights Analyst has the least. In fact, this latter role is increasingly likely be performed by an external business monitoring Page performance.
By assigning the appropriate role to your admins, you are guaranteeing increased security around how your Page will be used.
I recommend taking a look at this Facebook help information then review how your Facebook Page is currently being managed. If you have any queries, please feel free to get in touch.