It's more than that. Microsoft is acquiring the Lumia brand. This gives them the ability to bundle both hardware and software to create one simple, cohesive experience. They will no longer be pushing the Nokia Lumia with Windows Phone 8, but The Microsoft Phone. And they can now brag about how they are the smartphone with the best camera. From a marketing perspective, this makes lots of sense.
Lots of that is speculation on what I hope Microsoft does with this, namely adopting Apple's marketing simplicity and control of the user experience.
Microsoft hasn't had real anti-trust issues in a while. Windows 8 did lots of things they wouldn't have gotten away with 15 years ago; nobody's going after them because they don't really wield the monopoly power they once did.
My understanding is that Microsoft, like IBM and ATT before it, was permanently disallowed to do certain things? I understand that nobody is/has gone after them (yet?), but is that just prosecutorial oversight/prioritization issues, or is there actually nothing wrong?
For example, Microsoft is permanently enjoined from restricting OEM crapware preloads. OEMs are allowed to preload whatever they wish on top of Windows.
However, it's perfectly fine for Microsoft to bundle an app store -- so long as an OEM is also allowed to load its own app store. (As Lenovo is doing.)
As for Windows RT and Windows Phone, Microsoft can do anything it wants. When the news came out that Windows RT would only allow Internet Explorer and would only allow programs to be loaded through the app store, the EU competition commissioner said in an interview that he saw nothing wrong with it.
That's because the antitrust case defined Microsoft's monopoly to be over x86 operating systems. Windows RT and Windows Phone run on ARM. What's more, Windows RT and Windows Phone do not have anywhere close to a monopoly of the tablet or smartphone markets.
There may be some tying issues, but branding is not a form of tying.
Lots of that is speculation on what I hope Microsoft does with this, namely adopting Apple's marketing simplicity and control of the user experience.