That is a functional design. It is important to note the upper pipes are not near anything that can burn though that is good fireplace design in the first place. Those pipes are HOT!

The cool air pipe is well away from the fireplace so carbon monoxides and other combustion gases are not drawn into them (or superheated plasma). The system must be FULLY sealed except at the entrance and exits.

The fan is unnecessary as thermal convection will draw air into the lower entrance as expanding heated air exits the four upper pipes, but the fan makes it a lot more efficient (maybe too efficient; some regulation of velocity would be wise lest the room/home get too hot for comfort).

The pipes will possibly block firescreens full coverage designed to prevent embers from exploding outward.