alt Hacker NewsCMSs allow non-technical people to update the site - that's why WordPress, Drupal, and all of the shambling corpses of "digital experience platforms" still command the dollars and eyeballs that they do.
Go ahead and give your content people access to a static site builder and see how quickly the process falls apart. Static site generators are perfect for engineers but terrible for the marketing people that are the actual "customers" of your public-facing website.
I did this, and you are 100% correct.
I used Hugo, told the marketing people to send me a markdown file and I'd load it up to Hugo. That was clearly too painful for them. So I told them to send me a Word doc and I'd convert it to markdown and load it up. That was too painful. I told them to send me an email with the words and images and I'd work out the rest. That was too painful.
They got some marketing agency to rewrite the entire marketing site in Wordpress, and then we had to implement some godawful kludges to get our backend to redirect to their shitty WP host for the appropriate pages. It was awful.
But the marketing folks were finally happy. They could write a blog post (that no-one read) themselves in the actual CMS and see it go live when they pushed the button.
We spent thousands, in a cash-strapped startup, dealing with this bullshit.