The main content of a page is comprised of one or more content groups. While each content group can be thought of as a page section, that semantic meaning isn’t actually attributed to content groups by the templates. This allows you to craft (non-semantic) page sections from multiple content groups to meet your design needs.
You can create as many content groups as you need.
→ Details: Proliferating Data Definition items
Semantic page sections are defined with the <section> element and convey specific meaning about the structure of your page to assistive technologies, search engines, and such. They’re great to use in general, but leveraging them here would impose undesirable tradeoffs with regard to page design and layout flexibility.