Is PAC SWC Module necessary?

I have an Eonon branded RK3188 unit - I replaced an older Pioneer system that a previous owner of the car (2005 Jeep Grand Cherokee) had installed - his setup used a PAC SWC module, which the guys who installed my Eonon used as well - was wondering that since the unit itself seems to have wiring specific to the steering wheel function, if this module is necessary at all? I ask because there on the left side SWC, my middle button mirrors another button, is not recognized independently - I had previously installed a different Android Head Unit, and with that one, the buttons functioned properly -

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