Cool, thanks for helping me understand, @armonr :+1:  I was just curious how it was better :p 

Still, I'm guessing it may be slightly faster when using `self::` but quick googling about the differences in performance yesterday didn't bring me what I was looking for.

I definitely agree it's semantically better. However, it may cause strange results later while writing unit tests or creating subclasses of the class with overwritten constants ;) That's because the [limitation of self](http://www.php.net/manual/en/language.oop5.late-static-bindings.php#language.oop5.late-static-bindings.self).