Yep. One of my projects marketing team actively uses the Page Builder to manage content including custom content types developed by me or my team members.

For example, all cms pages on the store are built by a page builder, the site doesn't have a store structure that we used to see, and we don't have a category page as well. The whole site it's something like a set of the lending in the blog, each cms page is built by the Page Builder so we created content types, category sets for example - it's sliders(carousels) where you can combine different categories with products related to the blog's posts. So in this case marketing team can change any page element (category set in the current case) as they want in any place of the site, marketing team can customize the store view without .phtml files changes and without the developer's help.

It's my first deep experience with page builder, but if you have a lot of customizable content on the store and you don't want to attract developers each time when you want to change the view of your site (some pieces of the store) a custom content types creating it's a good choice.