Sticking my head above the parapet here.
I borrowed one of these when they first came out as I was very dubious about the claims. Ordered one for myself the next day as it was plainly a large improvement. Obviously the data is identical, TCP ensures that, but all other unwanted electrical noise is removed. Its that which doesn't get to the rest of the chain in your system. You need a revealing system (and a good room), but its certainly not snake oil in my opinion, just depends on your priorities.
Previously my streamer was plugged into a NetGear 24 Port Gbit switch which every other device in my house plugs into. Who knows how noisy that is, but I guess badly.
So I do appreciate everyone is going to say this is all in the digital world, and 0's & 1's are 0's & 1's, and they are, but those perfectly receivable 0's & 1's bring a load of crud with them, that can easily spoil the porridge.
For info the rest of the system is Innuos Zenith Mk3, Innuos Phoenix Net, Innuos Phoenix USB, Chord Hugo TT2 DAC, Chord M-Scaler, Arcam A49 Amps & Kef Blade 2 Speakers. (plus lots of snake oil cables, but thats another.....discussion)