At its heart, an admin panel is a tool for managing data. It must handle Create, Read, Update, and Delete (CRUD) operations flawlessly.
Unlike consumer apps, admin tools are often used for 8 hours a day. This changes the design requirements:
An admin panel is a dashboard for the "health" of the system.
Admins prefer seeing more data at once rather than having lots of whitespace. Compact layouts and "Dense" modes are common.