Notice how the other heading is not visible anymore? Opening a session narrows the buffer to show only what matters.
This automatically becomes focused when you scroll to the associated page.
This one also becomes visible. Notice the note counter on mode-line of the document.
When scrolling through the document, this works the same as other notes. However, it is useful when you are using note sync commands, which go through every note. When using those commands to sync this note, the document view is scrolled to the point selected on the document.
You may have multiple Org-noter sessions open at the same time, while always keeping the initial notes buffer intact, even though it narrows the indirect buffers!
(You can change the behavior and location of the notes window btw!)
This note is grouped with another one, and with things like this, you may organize notes however you want. Keep them tidy! Just so you know, even notes associated with pages may hold other notes inside. The session was created on page 2, where this note is!
Besides, there is a command to enable auto-save and resume where you left, and another to set a different start page for the sessions.
This is the same document, but as we are using indirect buffers, we may scroll and zoom differently! This is Org-mode!! You can use everything it provides, like inline $\LaTeX$ equations and babel!
Besides, and a great selling point, everything lives on a separate Org notes file, searchable, taggable, however you want!