Need clarification on fins!

Just got a brand new board as a birthday gift/early christmas gift to myself. It's a Torq TET 9'1 Longboard. I know it's a kook board, but I am a kook lol. This is my first hardboard.

It did come with fins (2+1 setup), but the website mentioned that you could run it as a single fin. What would the benefits to running it as a single fin be? In what conditions should I do that? Is it just as simple as taking the sidebites off and using the middle fin it came with? It's about 7.5 inches.