My feeling is that if Swift didn't have the requirement of very tight interop with Objective-C there would have only been one kind of object. Maybe just structs

My feeling is that if Swift didn't have the requirement of very tight interop with Objective-C there would have only been one kind of object. Maybe just structs with the option of heap allocation/reference counting or something like that. But that's not the world Swift was born into and so it has both classes that are optionally Obj-C compatible and structs