Memory Mapped files do exist in some form or another though. As the file itself. That's the point of memory mapping files. You can right now memory map every file on your computer. That's TB of files. There will be no physical RAM usage and no swap file usage unless you start to actually work with those files (at which point they will be paged in). This will show as 'committed memory' in task manager.

Your example above isn't memory mapping files. It's just allocating RAM. That does have to exist in RAM or the swap file. But that's not what 'committed memory' above shows. Which is the whole point. The column the article is telling people to use is misleading.