Udemy's appeal for PMP prep is the price — self-paced video courses at a fraction of most competitors' cost, often discounted further during sales. The exam's 35-hour education requirement is easy to satisfy this way (most Udemy PMP courses are PMI-registered for contact hours), but that requirement is separate from actually being ready to pass a 180-question situational exam.
Course depth also varies more on Udemy than on a single-provider platform, since quality depends entirely on which instructor you pick. Candidates typically cross-check a course's coverage of the People/Process/Business Environment split against PMI's exam content outline before buying.
The deeper gap is diagnostic: a Udemy course has no way to tell you which of the three PMP domains you're actually weak in, or whether your situational judgment on people-management scenarios is where it needs to be. Edureify's Diagnostic maps that on day one, and the Readiness Score keeps updating from there.