Why would I automatically share usage and diagnostics data? In my Android settings (Version 6) I have the option to activate "to automatically share usage and diagnostics data".

I suppose that this will help certain developpers - and of course Google - by getting statistics of my battery states and usage (as the title says).

But appart from getting "more wonderful and stable apps" in later versions, is there any specific advantage for me? I am asking this as a user and as a developper (who has noticed that many users have this option turned off). In our part of the world (Africa) we are still paying for data, so providing this information will cost me and other users real money.

Do you know about any more direct incentive? Like "better status" in the Play Store? Brownie Points with Google?

Or - at least - can I have access somewhere and see what Google is collecting about my own usage and my own battery performance? That would be an incentive indeed. I might find that I spend much more time with my phone than I think (or maybe that way I discover that my baboon is using it when I leave the room...).

Please do not hate this question; I have started investigating this subject today, because some of our apps have just started giving crash-reports on the Play Console, so am collecting any information I can - from the dev-side and from the users-side. Thank you.

Edit: Since the first answer is questioning my mention of battery-information in my initial question, I will paste here a short summary from a Google Android Account Help page which does mention battery-level:


  What information is shared with Google If you turn on usage and
  diagnostics, your device sends information to Google about what’s
  working and not working. For example, your device can send information
  like battery level, how often you use your apps, and the quality and
  length of your network connections (like mobile, Wi-Fi, and
  Bluetooth). None of this information is used to identify you.
can I have access somewhere and see what Google is collecting about my own usage and my own battery performance? 


Yes. Click on My activity to see what information is collected by Google regarding your app activities (if you didn't disable it). The data is just about how many times and when you used an app (unless Google chose not to reveal all the data captured). I don't know how this can help in improving app stability or performance

What it does with this information is not transparent and I never saw any information being recorded about your battery statistics

If you click on the hamburger menu and go to activity controls, you will see what it benignly tracks with seemingly useful goals (if you missed the sarcasm , see How Google is secretly recording you through your mobile, monitoring millions of conversations )

Bottom line - all your activites are being monitored to improve user experience etc but at a cost. Folks disable these not just because of data consumption but privacy concerns. Smarter folks manage to have minimum Google components - See Android without Google courtesy Izzy

Edit: 


Thanks to OP for pointing out that Google does collect battery information as claimed here. This was new to me but I couldn't find any way this information is available to end users ; developers seem to be able to see it in Android Vitals and maybe elsewhere
Note that you can't disable monitoring, you can only pause ; this means it would be reset to default if you factory reset your device or change your device and could be reset sneakily by OS update or Play Store update. It's better to keep checking periodically if your settings hold