Deleted files are not visible through the file system either. Deleted files in tmpfs are not stored on disk. The biggest reason to use memfd_create is that you

Deleted files are not visible through the file system either. Deleted files in tmpfs are not stored on disk. The biggest reason to use memfd_create is that you can seal the memfd so it cannot be resized, and then it's safe to mmap on another side of a trust boundary; if you mmap an arbitrary attacker-controlled FD, the attacker(/poorly written client) can make you segfault. Wayland uses sealed memfds to pass framebuffers.