You need both. The Corsair system you are talking about is designed with two boxes that separate two functions. The Lighting Node Pro is the controller that communicates with the Corsair iCue software utility (via a USB2 connection) and creates the signals that control the light displays. It has two outputs (that can be synchronized or run as different channels) that probably can handle one light device each without the Hub (I'm not even sure about that). But the design intends that you will use those outputs to connect to on or two RGB Hub(s) from Corsair. That Hub has NO smarts at all and cannot do anything to control the lights. All it does is accept from the Lighting Node Pro the signals it generates and pass them on to the lighting devices. It also gets power from the PSU (via a SATA power output) and provides that to all its lighting devices.
Corsair also has a new different unit called their Lighting Node Core that combines the controller and multi-outlet Hub functions into one box, but I do not know whether it can work with the LL120 fans.