Most streamers, not all, don't have the necessary CPU and memory to run roon core. That's the main difference. I keep my NUC in my office and a streamer in the audio rack, both on the same network. I have used a NUC directly connected to a DAC via USB. As long as you have a good modern DAC using asynchronous USB, for instance a Benchmark DAC 3, noise shouldn't be a problem.
Streaming into my Benchmark DAC3B in an all-Benchmark stack the differences between an Ethernet based streamer and a Fibre Optical based streamer was massive via DAC USB. My network is likely noisy with a lot of computers (about 10 machines for my work), network switches, etc...
I kept everything the same on the system except switching from a Sonore microRendu to an Sonore OpticalRendu. I also got a new network switch that had 2 SFP slots for the Fibre Optical. I do think the DAC3B was suffering from noise in the network. Or, the electronics on the microRendu was not as clean as the electronics on the OpticalRendu.