Logically, a small website should be built with static HTML and CSS. So why build an overly complicated infrastructure with a web application front-end and a database back-end (which needs to be regularly maintained) just to display a simple website?
In many cases, WordPress became the hammer looking for anything that resembles a nail.
There is a large percentage of decision makers who want to be able to update their own sites, despite barely being confident enough to use Microsoft Word. In actual practice, the odds that these decision makers will ever actually update their site is nearly 0%. However, despite this, they still want the capability. If I were to show them static HTML/CSS, I'd starve.
For me, Wordpress gives me an interface that I can show these people before they decide to hire a quack who uses Wordpress for everything.
I've sometimes thought of a business model where I'd do content updates within 24 hours, but that just seems insane.
You could spend a lot of time thinking and examining requirements and come to the conclusion that a static site with very minimal but carefully designed styling would be an effective solution.
But it's hard to ask for thousands of $ for that with a straight face when the competing bidders are offering CMSs , iphone apps and facebook integration for the same price.
Then I go to my browser, hit F5, and presto, my change is displayed.
Ahhh, and I don't even use CSS! Only html5.
I use the following tags: h1, h2, h3, h4, p, ul, ol, li, br, strong, and i.
I use © and &
And I let the browser render as it wishes.
Famous last words. The day when it's not an easy fix, you're stuck with bad code live in production affecting all users until someone can fix the bug. Worse, the only way to verify that the fix works is to check your assumptions against the live system aka a nightmare. Of course, none of this matters if your site is a personal blog or something that doesn't affect anybody's business, but nothing really matters in that case.
I've found it effective at abstracting away browser differences.