Comment by deadbunny

Backups. If a program properly follows the spec I can just `rsync ~/.config/foo` or store it in a repo and not have to worry about it. If a program doesn't follow the spec I now have to write program specific filters for rsync/custom .gitignore entries to avoid backing up state and cache. Now multiply that across dozens of programs written by lazy devs who don't want to write 12 lines of code to determine the correct location for their files.