Edge in its current form is being replaced by a version based on Chromium. I can see why people would want to use that when it becomes default since it would have the advantages of using Chrome but without the extra download.
It'll on the default install of Windows 10 once 1.0 is formally released. When people realize it's Microsoft Chrome then they'll ditch Google's version of Chrome. It's actually a pretty smart move by MS as they'll quickly become the dominant browser again.
Beta downloads: https://www.microsoftedgeinsider.com/en-us/download