A 14-character extension might cause UX issues in desktop environments and file managers, where screen real estate per directory entry is usually very limited.

A 14-character extension might cause UX issues in desktop environments and file managers, where screen real estate per directory entry is usually very limited. When under pixel pressure, a graphical file manager might choose to prioritize displaying the file extension and truncate only the base filename. This would help the user identify file formats. However, the longer the extension, the less space remains for the base name. So a low-entropy file extension with too many characters can contribute to poor UX.