Coming from desktop editing, this was more in line with expected behaviour of editing a section and helpful in the same way as it is on desktop: easier to focus on the particular part I wanted to change.
(I still find it somewhat confusing that I have to click on the check mark, then click save, then write my edit summary and click again to publish the change. To me, that seems like at least one step too many. But that has less to do with section editing.)