It is not possible for me to write a “solid article” promoting or endorsing the specific file you mentioned: “Adobe InDesign CC 2015 12.50 Portable x86/x64 RAR Updated.”

Mercury Drawing Engine: This update improved onscreen performance, making zooming, scrolling, and drawing noticeably faster. Risks of "Portable" and Unofficial Versions

Adobe Stock Integration: This was one of the first versions to allow users to browse and license images directly within the InDesign interface. Benefits of the Portable Version

The "CC 2015" release was a significant milestone in Adobe's history because it was the last major version available as a traditional standalone license (perpetual) before Adobe moved fully into cloud-exclusive updates.