Some are highly selective, like Chicago, so you should not have thought that you could get into them easily.
Others may appear to be “safeties”, but they tend to waitlist “overqualified” applicants whom they believe will not attend, unless they show a high enough “level of interest” (i.e. recorded visits, checking the portal, reading emails from the college with an email reader that displays images, etc.).
Waitlist should generally be seen as a rejection, with a very small chance of admission after May 1.