This is some "net promoter score" cult thing that somebody thinks is an appropriate metric to be judged on. The metric is dumb enough even if it could be accurately measured, but it's also one of the noisiest possible things you can sample, especially when your method is to ask it in an offensive and annoying way that interrupts someone who is trying to work.

I use office over google docs for various business reasons, but I have so much ill will towards Microsoft from how annoying they are with notifications. It's like they think buying their software is a license to pester you.

Oh, you must be right, I hadn't made the connection to the NPS.

It is particularly unfit for Windows, because of the extreme network effects that have solidified Windows dominant position. Nobody really chooses Windows, it's just the default. If anything, people will wonder, "wait, I can choose something else?"

NPS can be useful in certain contexts, especially when communicating in large organizations, even though it can be noisy and is usually annoying to be nagged about as an end-user.