Coursera has increasingly pushed
non-participation in a course's verified certificate process as a signifier of
lower status as a student. Originally, certificates were a mark of academic performance and the business model was more akin to a dual license open-source project where the non-paying community was just the non-paying community; the verified certificate was solely a value added proposition based on the value of verification. The change has been that certificates have shifted toward a mark of consumer status.
There has been a trend toward attaching stigma to taking the courses for free. Removing the certificates from free tracks is an obvious part of it.