What does "to the edge" mean?

When I right-click on a toolbar?

This option is used to make two toolbars on the same desktop side. I've prepared the video to show how this option works.

But I can already do that, without using "to the edge". I am using standalone TLB, which appears to allow any number of toolbars on the same edge of the screen.

Yes, you can. But only if both toolbars without the "taskbar mode". Taskbar Mode make toolbar "like a taskbar". So the maximized windows don't overlay the toolbar position, also the desktop icons can't be under the toolbar.