@zlone - good. Ah, but manufacturer claims improvements in transfer :-) so it is already subject to truth in advertisement.
Next, here is quote from the iFi site - "The LAN iSilencer removes the electrical noise that distorts the audio signal from your network." Huh? What audio signal in my CAT6? Where?
Now, if noise to streamer is an issue. First, it is a twisted pair, correct? So we are talking POOR implementation of the input analog receiver and ADC in the network hardware of the receiver. Sounds unlikely since chips and solutions are 99% standard, nothing is custom there.
So next, you may say - leak EMI from network cable over to.... where? If streamer is combined with DAC - maybe... Get a shielded cable then. If streamer is an ARM PC with USB out - unlikely. Digital to digital over controlled protocols with recovery.
Decent DAC is immune to USB noise and would have isolation at the input. In the worst case DDC like Denafrips Iris in front of the DAC would be a much better choice.