* Some teams do this already with git data...but if it's free as part of a team's development platform then maybe the less sophisticated managers who don't know how to interpret the data will misuse it?
* If the editor is heavily instrumented then even more granular "productivity" metrics could be extracted, like time spent with the tab active, etc. which aren't available with a vanilla install of other editors. ¯\_(ツ)_/¯
In the end, obscurity is just not a durable defense. Better to earn trust with good managers, and avoid companies that let bad managers flourish. If you don't have the ability to quit a bad manager or bad working environment, then no amount of tooling choices by GitHub/Microsoft was going to save you anyways.
Oh boy. Had chills from my time as a Jr. Engineer at Accenture. Still remember the day a manager looked at me like I offended his entire family for saying that lines written didn't mean productivity achieved.