It's there to show scale. Like when people put a penny next to an object in a photograph.
On topic: This hard drive is incredibly impressive, and it's fascinating to see how the density changes between a 1K HDD and a 4k HDD.
Assuming that it's a single person? The use of "our" in the description (as well as the fact that they've got an online map in the last picture!) suggests that this is on a shared server.