This request was raised during user testing conducted by @iamjessklein . The user requested the ability to add a new section while editing using the section editing interface. This was not part of the original scope of section editing, but is a feature we should evaluate for future iterations.
I agree this is a feature we should consider for future iterations; however, I think any conversation around prioritization is better suited for a time when we have feedback – quantitative and qualitative – about how it's being used by people outside of a testing context.
Related: I think it's important to mention this particular instance of feedback – to which this ticket is a response – comes from someone who does not edit on mobile or with VisualEditor (see the ~25 seconds beginning at 3:52). I say this as a reminder to ask our future selves questions resembling: What is the relationship be between editing on mobile and editing on desktop? What should contributors expect from the mobile editing experience?
Also, @matmarex in mentioning that editors contributing on desktop have the ability to add new sections [via format menu > Heading], are you suggesting those same editors are likely to expect similar functionality  to exist when contributing via VE on mobile? Just wanting to clarify b/c as you mentioned, there currently is no option - I've seen – to add new sections on mobile VE.
- "...ability to add a new section while editing using the section editing?"