Given this reference text, what are column stores used for?

A column-oriented DBMS or columnar DBMS is a database management system (DBMS) that stores data tables by column rather than by row. Benefits include more efficient access to data when only querying a subset of columns (by eliminating the need to read columns that are not relevant), and more options for data compression. However, they are typically less efficient for inserting new data.

Practical use of a column store versus a row store differs little in the relational DBMS world. Both columnar and row databases can use traditional database query languages like SQL to load data and perform queries. Both row and columnar databases can become the backbone in a system to serve data for common extract, transform, load (ETL) and tools.

A column store database stores data as any other database management system. The data itself is stored sequentially to improve the performance of scans on a subset of individual columns.