This is being reflected in a similar rollout on other Windows 10 form factors, of course, plus the Web and storefronts/apps on other platforms.
Not that this affects Windows 10 Mobile users unduly, it's just a name change. But in terms of the wider ecosystem it opens up the possibilities of what the Microsoft Store might sell. And, as intimated in the last podcast, it wouldn't be totally unheard of for a future Microsoft Store to offer phones based on Android but loaded up with everything Microsoft. Everything, that is, except Windows.
This does all fit in with the Google and Apple Stores, of course, all of which are company-centric rather than computing platform-specific in 2017.
From Windows (and other) phones, to wearables (e.g. Fitbits), to laptops, 'Mixed Reality' stuff, accessories and Office 365 subscriptions, there's a lot that a Microsoft Store would (and already is) selling.