There is indeed a way for technical users to troubleshoot battery usage, although this does not necessarily help even technical users when the app turns out to

There is indeed a way for technical users to troubleshoot battery usage, although this does not necessarily help even technical users when the app turns out to be important. iOS tends to make it significantly harder for applications to justify background processing, so I myself tend to find battery statistics less useful - you have apps which have a more voracious appetite than others, but typically only when you are actively gaining value from them.