It's from Microsoft. Many companies love to be very tightly tied to Microsoft, for some reasons. I never really understood the actual underlying reasons. Perhaps Windows 95 was that good and it's brand loyalty since.

Just like Amazon, Google and even Vercel have their own distros.

To have full integration with their cloud services, instead of a random purpose Linux distro.

And accountability.

Because someone has to be accountable, right? In business practices, having no clear party responsible for an area you don't fully understand is a difficult problem. Ultimately, I think it's a matter of accountability. Regardless of how lightweight and good Linux is, Windows is still a bit more convenient on the GUI side.