Long term risk management!
99% of my time in front of the computer is spent in an editor (for both work and play). Having invested and continuing to invest so much time and effort in my tools and my environment, I would hate for something so fundamental in my life to not be free as in freedom:
"Microsoft's releases of Visual Studio Code are licensed
under this not-FLOSS license and contain telemetry/tracking"
https://code.visualstudio.com/license
By choosing open source, you can reduce the amount of carpet pulled out from under you.