If you are using Friendly URLs in your website you must use Content Search Web Part to build content aggregations.
One of the new capabilities of SharePoint 2013 for public-facing websites is Managed Navigation. Managed Navigation allows you to specify one or more Friendly URLs for each of the navigation items. This helps you optimize your website for Internet search engines and helps you preserve existing URLs when migrating from other content management systems.
In the past, when building content aggregations, you would most likely use Content Query Web Part. Although it is still available in SharePoint 2013, Content Query Web Part unfortunately doesn’t support Friendly URLs and when used for building content aggregations in a website that uses Friendly URLs, it will display the physical URLs instead. In order to preserve Friendly URLs in content aggregations you have to use the Content Search Web Part.