@eyemgh Can you clarify what you mean by weakest candidates? If that were the case, wouldn’t that mean it would be less competitive?
The first cut includes all candidates regardless of how strong their stats are. Certainly many of them will be very well qualified, but some of them won’t be. Roughly 10% of that pool gets admitted. Then they give out waitlist spots. Those only go to the remaining top candidates who didn’t get admitted. The bottom candidates aren’t offered waitlist spots. Only 4% of them get in. Essentially, waitlist students are competing against the best of the best of what’s left and even a lower percentage of them get in.
Also, wait lists are not necessarily rank ordered for any given school. If a college has too low a yield overall and in a certain profile of student, the most similar students on the wait list are more likely to be admitted. For example, if the school underyields, and the underyield is greatest in prospective CS majors, that improves the OP’s chances of getting in off the waitlist. On the other hand, if the underyield is in other prospective majors and prospective CS majors had an overyield, then the OP is unlikely to be taken from the wait list even if others are. Other applicant aspects may also be relevant.