In common sources, I see a great deal of use that can come from defining the institutions of mass society as business, civil society and government. When the roles blur in how institutions define themselves, they blur within a system of domination using these three sectors.
For instance, take the media. In many anarchist analysis, the media is a part of the state and in reality, the media is often directly controlled as a government entity, though in America, the media is treated as an institution of business. Also, despite if the strong arm of the media is held directly by the government or not, independent diy journalism even in these cases, which could be classified as part of civil society more than part of government.
To me, the definition of the state is more useful when defined in relation to a system of domination where the state is a player, an important player, but the responsibility of control extends even beyond its role. With so much cross over between various institutions (social welfare in all three sectors, for instance) we can see both similarities and differences between them despite each institution play a part in the system of domination.
What this means to me is the state can get more strictly defined as government, but government is not where power is exclusively held anymore. So the contrary question to this one is why use an expanded definition of state, when developing a strict definition within a system of domination would probably explain the institutions of control just as well, if not better?
Hopefully that didn't come off as loaded and I'm not wed to it, but it would seem to be a good point to provoke further thought through discussion.