The underlying difference
WordPress builds each page at the moment somebody asks for it: it queries a database, runs the theme and the plugins, and delivers the result. A static site delivers a file that was already made.
Almost everything else follows from that. Static is faster because there is nothing to compute. It is safer because there is no database to inject into and no login screen to attack. And it costs less to host because any content network will serve a file for next to nothing.
What WordPress gives in return is an enormous ecosystem: thousands of extensions, plenty of people who know how to work on it, and an editing panel almost everybody recognises. None of that is a small thing.
The year-three question
A freshly built WordPress site is fine. The trouble arrives later and always by the same route: the theme and the plugins need updating, updates sometimes break things, and in a small business nobody’s job is to watch for it.
By year three, an uncomfortable share of small-business WordPress sites are out of date, throwing security warnings, with a plugin whose author abandoned it. That is not WordPress’s fault: it needs continuous maintenance, and almost nobody budgets for it at the start.
So the useful question is not which is better today. It is: who updates it in March three years from now, and is that cost in the budget?
When WordPress is the right answer
There are clear cases and they are worth stating, because this site is built without WordPress and that is not an argument. If you publish several times a week and several people edit with different permissions, the WordPress panel is designed for exactly that.
If you depend on a particular extension that only exists there — a sector-specific booking integration, an unusual payment gateway, a membership system — rebuilding it elsewhere costs more than you save.
And if whoever is going to maintain it already knows WordPress, that familiarity is worth more than any technical advantage. A tool people actually use beats a better tool nobody opens.