It’s true that for many people an intelligent Siri is unimportant— they barely use any of the phone’s capability now. Those people could use a 1990’s era cell phone.

But they won’t. One of the main reasons is cameras, even if they hardly ever use it. But if (for example) they are told “You can tell Siri to flip this picture 90 degrees and zoom in 100%”, they’ll buy the new phone.