When editing in any NLE (non-linear editor) markers are exactly that, a way to mark sections of the timeline for easy navigation. Like editing in Sony Vegas, if I have a scene @ 0:12 (12 minutes) I would place a named marker at the start of it, or a region marker around the entire section, to jump directly there and edit there at any time.
Typically, those markers and regions are presented in menu lists so I'd click a menu list and select "Jim Talking to Kate" and jump directly there... or in the case with regions, jump directly there and horizontally zoom the timeline to that area.
It's why all good audio and video NLE's have markers and regions, because navigation tends to get tedious without them.
In this case they would look much like the red loop markers on the timeline look now, but being different colors, and also having names for identification.
Here's a graphic example of regions and markers. In this case, I would just press the number on the keyboard (1, 2, 3) to jump to those markers.