These act as the "roots," attaching the hair to a surface and holding the hair's state (dynamic, static, or passive).
The Pluralsight (formerly Digital Tutors) training outlines a specific, professional workflow to achieve high-quality results: Digital Tutors Understanding The Basics Of Nhair In Maya
This is the visual representation of the hair. While the curves drive the motion, PFX provides the actual "look" and volume that appears in renders. Standard Workflow for nHair These act as the "roots," attaching the hair