Related tables use data efficiently.
Access is different because it uses related tables. It's designed so that one table can find and use data in another table. That way, when you keep track of work items, for example, there's no need to type employee names or project names that you've already stored.
The picture shows this. You enter a new task in the Tasks table. As part of that, you select a project number from the Project field, which uses data from the Projects table. Also, the Owner field in the Projects table uses data from the Employees table, and that means the Tasks table and the Projects table both know which employee the work is assigned to. In turn, that helps you know who the work is assigned to. Related tables make Access more efficient than lists or worksheets.