According to the docs [0] it's in part due to an unequal comparison: "[WinFsp] outperforms NTFS in most scenarios (an unfair comparison as NTFS is a disk file system and WinFsp is tested with an in-memory file system)." I guess the point is just that WinFsp is fast enough for practical use.
Yeah, I assumed it was going to be an in-memory comparison but that’s super misleading and doesn’t let one get a sense of the overhead of the system itself.
[0] https://github.com/billziss-gh/winfsp/blob/master/doc/WinFsp...