I understand that the meaning of atomic was explained in What's the difference between the atomic and nonatomic attributes?, but what I want to know is:
Q. Are there any side effects, besides performance issues, in using atomic properties everywhere?
It seems the answer is no, as the performance of iPhone is quite fast nowadays. So why are so many people still using non-atomic?
Even atomic does not guarantee thread safety, but it's still better than nothing, right?