System catalogs are internal tables and views that provide system-level metadata about objects stored in a database. In SQL Server, accessing these catalogs can be cumbersome due to their scope being limited to individual databases, making it difficult to compare results across multiple databases. In contrast, Couchbase's system catalogs are scoped at the cluster level, allowing for easier comparison and analysis of database metadata. This simplification enables developers to access and analyze database objects with minimal code, making it a convenient approach for database administrators. The text highlights the differences in terminology between SQL Server and Couchbase, demonstrating how these NoSQL databases can simplify tasks typically associated with relational databases like SQL Server.