> I can easily control how much battery life is remaining on my phone by plugging it in.
Except when you can't. Are you really always near a power outlet? There have been plenty cases where I just haven't been able to charge my phone and have had to turn it off rather than use it for what I want.
> I can't control how much of my data plan an app is using, except by uninstalling the app.
Depending on where you are, get an unlimited data plan. I know not every country has these, but most do.
I'm in the US. My data plan is capped when I'm on my carrier's network, and unlimited (and much more expensive) when I'm roaming. Typical US carrier.
This highlights a good point: it's not just the number of bytes of data, it's the cost per byte. Many data plans have an explicit cost per byte, but even ones that don't will have an opportunity cost: if your app is sucking up a portion of my bandwidth, you're preventing my other apps from retrieving data. Even if my data was free, my bandwidth is limited.
Except when you can't. Are you really always near a power outlet? There have been plenty cases where I just haven't been able to charge my phone and have had to turn it off rather than use it for what I want.
> I can't control how much of my data plan an app is using, except by uninstalling the app.
Depending on where you are, get an unlimited data plan. I know not every country has these, but most do.