The Use Case Glossary is typically in table-format to show who can use the system in different ways. For instance, you may want the accountant to update invoices but you want the warehouse employees to avoid that section. It's easy to set up the information system to allow each department access to different parts of the system based on their login criteria. Here is an example of a simple table for a small company to show who can click where within the system:
The Use Case Model is a visual diagram to show which "Actors" can use each part of the system. Users in the world of information systems are call Actors, and each actor has specific areas that they can access. Every class and job function I've done in the web design field requires both written and visual layouts. Sometimes a visual diagram can bring ten pages of words into a single page with arrows that makes perfect sense.
Whitten, Jeffrey L., & Bentley, Lonnie D. (2007). Systems analysis and design methods, 7th edition. Boston, Mass.: McGraw Hill.