Digital isolation between Ethernet hub and streamer

I can honestly say it does make a SQ difference. I have my Ethernet cable from my router to my Synergistic Research switch then the long thicker cable of the Muon Pro from the switch to my Aqua LinQ transporter connected with the Muon Pro shorter and thinner cable and the LinQ connected to my Weiss 501.Network Acoustic offers a 30 day no questions asked refund if you are not satisfied, so for the skeptical people it is a no brainer. I have been experimenting for years and honestly this is the best i ever had. How can we make a judgement without even trying?

https://forum.audiogon.com/discussions/stack-audio-smoothlan-network-filter-wow

There was a long thread started by Ozzy late last year on the Smooth Lan; seems a few members tried and liked what it did. (myself included)

As far as I can tell, these filters provide galvanic isolation in one of two ways, by either using transformers (i.e., the NA filters) or optical isolation (i.e., GigaFOIL and others).  Don't most good servers/streamers also provide some form of isolation?

The last cable my streamer sees is a fiber optic cable but, even when it was an Ethernet cable, none of this stuff made a reliably discernable difference in the sound of my system, and I have owned the NA eno and muon systems (including their Ethernet cables), GigaFOILv4-INLINE, and others. I could say I heard differences, but that would require talking myself into it, YMMV.

I have the Network Acoustics (NA) Eno2 'Ethernet Filter' system with the NA LAN cables (the cables come with the Eno2 as a package deal option) and it made a significant difference immediately noticeable in soundstage dimensions, image clarity and instrumental separation. The science behind devices like these is readily available on the internet. More importantly, in a higher end system devoted to digital sources like mine, the devices simply work their magic, and apparently for many others as well.

I just don't get why, BEFORE open-minded experience of these devices in one's own system, one would discount their efficacy.

They work for some and for others not so much. Kind of like power cables and the like.  Don't be a binary thinker (cuts both ways) and just disqualify the product or people's position on that given product, positive or negative.