You’re not missing anything. If you want, you can put your NUC in a fanless case. Otherwise, no difference.
Roon Nucleus vs generic NUC
I run Roon ROCK on an Intel NUC with an i5 processor. It gets power from an HDPlex linear power supply and is connected to a Synology NAS and the network via an EtherREGEN switch. This gear all sits on an old audio rack in a separate area from my listening room, so I don't hear the cooling fan on the NUC.
My question is whether there would be any conceivable, audible benefit to replacing the little three-year-old NUC with a Roon Nucleus, which I suspect is an Intel NUC inside a fancy (and pretty) heat-sink case. I don't do Roon signal processing much, although the few times I've tried it the NUC could handle it.
Am I missing something? Any thoughts—and particularly experiences—would be appreciated.