Just by showing the top line alone, you reveal os and version, plus sometimes patches, service provider, VPN connections or lack of, Bluetooth enabled or otherwise and so on. Security software, NFC enabled (or otherwise)....
The last big update on my android changed the battery indicator (a couple of months ago). It sounds trivial, but someone still showing the old battery icon paints a target saying these patches have not be applied to my device. Plus service provider, someone now knows who to pretend to be, perhaps there's not too many providers where you are, but it's all tiny bits of information. In my top line is also the security software I'm using, along with a while loadof other bits of they are enabled at the time.
My phone/security software does not let you give that top line because it gives so much info away. It physically will not screenshot that section any longer. That's how much info you're giving away.
And the target is huge. People write software and sell it that automates access to devices based on what patch they have or don't have. All you need to do is to ID the victim, put in a few settings and press or write start and hit enter. The software does the rest.
My course of ethical hacking was fascinating and worrying at the same time and in equal measures.