It's abstraction. Your not supposed to care that the setter is doing anything. The class is providing you an interface -- what it does with that interface is not your concern. I hate to quote Alan Kay but all objects should just respond to messages. Whether that message corresponds to a method or a property is pure semantics.
I sometimes use getters and setters to provide backwards compatibility. What was just maybe a simple data field a decade ago doesn't even exist anymore because some major system has changed and we aren't rewriting every single application when we can provide the values that they need easily enough.
If you know that setters exist then you already know that the code can do more. It's not a huge mental leap from property setting to method calls. You should never assume anything is infallible. I don't think classes should even expose raw fields.
I sometimes use getters and setters to provide backwards compatibility. What was just maybe a simple data field a decade ago doesn't even exist anymore because some major system has changed and we aren't rewriting every single application when we can provide the values that they need easily enough.
If you know that setters exist then you already know that the code can do more. It's not a huge mental leap from property setting to method calls. You should never assume anything is infallible. I don't think classes should even expose raw fields.