By now, you know that Drupal works with the two directories active and staging. But what is the intention behind those directories? And how do we use them?

The configuration used by your site is called the active configuration since it's the configuration that is affecting the site's behavior right now. The current (active) configuration is stored in the database and direct changes to your site's configuration go into the specific tables. The reason Drupal 8 stores the active configuration in the database is that it enhances performance and security. Source: https://www.drupal.org/node/2241059.

However, sometimes you might not want to store the active configuration in the database and might need to use a different storage mechanism. For example, using the filesystem as configuration storage will enable you to track changes in the site's configuration using a versioning system such as Git or SVN.