Actually, I think it depends on the use-case. I mean, there are some use-cases which are inherently battery intensive. Like accurate position tracking or receiv

Actually, I think it depends on the use-case. I mean, there are some use-cases which are inherently battery intensive. Like accurate position tracking or receiving real-time messages. I think the problem is, that many users do not know which apps require more energy due to the specific problem they solve and which apps are just badly engineered. So to let the user decide every case is a bad option (+ decision fatigue). Letting the developers decide is even worse, as they would simply say, that their app requires as much energy as they need. So the vendor thinks he has to make that decision (as they don't want their phone to being perceived as having a bad battery life), who neither knows anything about the specific app nor about the use-case (probably the worst option). I think the system should simply report battery offenders (above the threshold of a well-engineered instant messaging app for example) to the user in a manner of 'App X used Y% of your battery in the last 24 hours. By limiting the battery usage, the app might not function as it is supposed to be. Do you want to limit the battery usage of this app?' That way, most developers would have a chance to build good apps which do not get reported and users would stay in control.