While the capabilities of various features can certainly drive the selection of one Tiki Feature or another, I tend to think that at the core, a website should have a "Knowledge Architecture" that drives selection of where to put content.
Implicitly this also drives ongoing development of Tiki features, and over time "the story" of what to use when can evolve so that Tiki websites, will naturally follow what the community has established as "best practices" and consequently made the "path of least resistance."
I believe that if you want to write something that will hold up over time, you don't want to write it in a context that will make it appear dated and irrelevant. Hence, you do not blog it (or email it).
But you can certainly link to it in shorter blog posts where you put a personal or timely spin on it. The blog can also be used to direct visitors to timeless content that is buried somewhere in the site.
For me the question then becomes: "Wiki or Article?" I haven't fully answered this in the context of a website that is not highly collaborative. Elsewhere on this site, I saw the statement to the effect that "Articles are fixed at the time that they are published and Wiki pages are fluid." (But EVERY Wiki page doesn't have to be fluid, so.... I am still questioning whether articles are needed)