They used in specific cases where you are off loading workflows or jobs to other AEM author instances. So for example if you have a large DAM implementation with frequent asset uploads you might choose to off load the creation of renditions to dedicated server in order to better scale you authoring server for content editing. See http://docs.adobe.com/docs/en/aem/6-0/deploy/configuring/offloading.html for details.
They used in specific cases where you are off loading workflows or jobs to other AEM author instances. So for example if you have a large DAM implementation with frequent asset uploads you might choose to off load the creation of renditions to dedicated server in order to better scale you authoring server for content editing. See http://docs.adobe.com/docs/en/aem/6-0/deploy/configuring/offloading.html for details.
