Question

With ARC, every pointer assignment does a retain by default. In that light, in noatomic cases, why do I even need to declare properties?

How are these two any different?

//Property
@interface I1 : NSObject 
@property (nonatomic, strong) NSString* str;
@end

I1 *obj1 = ...;
obj1.str = [[NSString alloc] init...];

//Only member variable
@interface I2 : NSObject { 
@public
    NSString* str;
}
@end
I2 *obj2 = ...;
obj2->str = [[NSString alloc] init...];

Answer 1

Memory management is not the only advantage of using properties.

Two in particular that come to mind for me is:

1. KVO (without having to manually call willChangeValueForKey: and didChangeValueForKey: – see Manual Change Notification)
2. Ability to write custom logic for a setter and getter as well as write subclass customizations for the setter and getter.

bbum wrote a great response to this in iOS: must every iVar really be property?