Much like any other app store, the Windows Store has a set of rules that must be followed in order for an app to be listed. Google decided to ignore those rules, and Google Chrome lasted less than a day in the Windows Store.
The listing for Google Chrome that appeared in the Windows Store was simply an installer app that loaded a link to download Chrome instead of loading a Microsoft-compliant version of the browser. As soon as Microsoft noticed, the listing was taken down.
As to why Google would take the time to try this, according to The Verge it was an attempt to combat the fake Chrome apps already present on the Windows Store. Microsoft can’t keep them out of the store for some reason, so Google tried taking the matter into its own hands. It failed, meaning getting Chrome requires using Microsoft Edge to download it.
Google isn’t commenting on the app takedown, but what could it really say about the matter? Google would never agree to use alternative engines inside Chrome, so the search giant’s browser will remain off the Windows Store indefinitely. If you see it there, chances are it’s a fake app.