While the iPhone 6S can certainly do the same functions, it is not as seamless as it is on the Moto G3. Apparently, the iOS 9 has made it a little more tedious to do all those functions on the iPhone 6S compared to doing it on the Moto G3. And that is the reason why it is considered by critics as a better smartphone compared to the iPhone 6S.
Accordingly, the iPhone 6S has great hardware but it continues to be hobbled by its software, referring to the iOS 9, which lacks proper file system.
Although Apple has attempted to open up its operating system a bit, it is still limited when compared to Windows, Android or even the Mac OS X. And that is the reason why that despite a great-looking iPhone 6S, its OS simply makes life a little difficult for its users.
For instance, in an Android phone like the Moto G3, if a user wants to play a song on his smartphone from a computer, he can just connect the phone to the PC and copy-paste it. But on the iPhone, it cannot be done the same way. And everything holds true for all other files needed to be played or viewed on the iPhone.