Because it’s the most flexible, and therefore the best.
Seriously, that’s all there is to it.
A few years ago, I tried to create my own content management system. I wanted it to be super easy to use, yet flexible enough to be used for a wide variety of sites. And I actually got pretty far with it. You could blog, update static content, manage users, manage uploaded media, and a few other things.
But the more I worked on it, the more I realized that I was recreating WordPress.
So I switched to WordPress, and haven’t looked back since.
But even WordPress isn’t perfect. It can’t do everything. It isn’t built with every scenario in mind. I mean, that would be impossible, right?
The cool thing about WordPress is that any developer can make WordPress the perfect platform for them through installing and developing plugins. Plugins make WordPress even better.
If you want to automatically share your posts to twitter, you can just install the plugin WP to Twitter.
If you’re anticipating a lot of traffic, and you want to do all that you can to help your host handle it, you can install a plugin cache your pages. I like WP Fastest Cache.
When I wanted to be able to focus on blogging, and not worry about finding the perfect image for it, yet still have a unique image attached to each post I write, I created a plugin to generate an image based on the title of the post.
No matter what you want your website to do, WordPress is the solution.