Correctly configured it is a static site with a minimal stub in PHP.

And if you want to go further you can bypass that stub and serve the static pages directly from your web server.

Best of both worlds, really.

> Correctly configured it is a static site with a minimal stub in PHP

Maybe there's a 1001 plugins being used which means the Wordpress site has to make boatloads of requests to the backend. Many Wordpress sites make that mistake. I keep my plugin count to at least five plugins. And they're obviously plugins which I really need, and they're not chatty in any way.

But the sites that are slow or performance sensitive often aren't just static sites. If it's more than just a simple CMS to you, you need to be enough of a WordPress expert that you probably don't need WordPress in the first place (or you're just using it for the themes or plugins). Weird WP performance cliffs are hard to avoid for dynamic content and "correctly configuring" either means rolling a custom solution or getting neck deep in your infra—both of which smell a lot more like engineering than not.

I've only run one wordpress site (and reluctantly), but I found it very hard to configure correctly. I was very happy when I was able to convince my boss to replace it with a much simpler blog system that only supported exactly what we needed.