Dog collars don't break away when tugged on, which is good because they're used to attach a leash. It's problematic for cats though because cats like to climb on things, and if their collar catches on something, it can choke them if they fall or try to jump down.

Cat collars are designed with this in mind. They have a buckle that will release if pulled on with enough force, so they won't choke your cat if they get stuck on something.

TL;DR dog collars can choke cats