Its just as easy to take a photo as it is to hold down the home button. Am I missing something here?
Maybe for a remote trigger, set the phone up for a photo, get people organized, "Siri, take picture", *click*. "Siri, zoom to 5 times and take picture" *click*
Also, if it could be used in a series of events like a macro, "Siri take picture and send to wife with message "Check out this sunset".