@rjkofnovi, a selective school may have another reason to have ED instead of EA besides the admit rate. For instance, if they want a student body where a large percentage have that school as a first choice because they believe that would make for a more cohesive student body.
In any case, besides HYPSM, having EA instead of ED doesn’t seem to hurt UChicago, Caltech, Georgetown, ND, or BC when it comes to acceptance rate.