I know that this isn't 100% true. I understand that Parallels is a Mac application, but Windows isn't. On my MacBook Pro I had a Bootcamp partition with Windows 8.1 installed. I eventually installed Parallels and accessed the 8.1 Bootcamp installation through Parallels so I wasn't rebooting my computer to access Windows. To this day on my MacBook Pro, Windows 8.1 is reading/writing into the Bootcamp NTFS partition.
Since I know that it's not required to have an NTFS partition, let me modify my question. Is there a performance advantage in creating an NTFS partition for Windows to operate in when running it through a Parallels VM?