While permissions determine which actions individual users can take, the extensions you configure in Settings > Extensions control the overall enablement of certain features in the platform, such as the reply assistant, customer satisfaction surveys, and automatic exports. Other features, such as Routing mode, are controlled by a setting in Settings > Account settings.
For a user to access and use a feature in the platform, he or she must have the necessary permission, and if an account-level setting exists for enabling the feature as a setting or extension, the feature must be enabled.