Using optical filter for ethernet

Just saw a demonstration that claimed that introducing an ethernet-optical-ethernet filter would filter out lots of radio frequency interference that comes from the web, your modem, and your ethernet devices like a NAS where you store your music. Basically a pair of optical ethernet converters back to back. Cost under $100. The demo at last year's Denver Audio Fest claimed it makes a sound quality difference. Call it an optical filter. I think its ListenUp who gave the demo. As an example they suggest you put this filter between your streamer and your NAS. Bacically any components connected via ethernet cable evan within your network, not just to the outside world. Any thoughts or experience?
Ethernet transmitters and receivers are balanced,and galvanically isolated.

It's also very high speed, compared to streaming needs.

It would certainly be interesting if something like this makes a difference.
Sonore is in pre-production of their upcoming opticalRendu which takes this concept even further. Chris Connaker posted a short video on YouTube about it yesterday: