All one has to do to know Graphene is real and not snake oil and see the potential value of graphene in electronics in general is some simple google searches.
The trick with any useful new innovative technology is always in the proper application. Any current applications for wires, fuses etc. are most likely limited still and the value not always clear case by case. The devil is always in the details. But over time, I am optimistic graphene will assume a larger role in more electronics in general based on its unique and useful physical properties.
Meanwhile, it is not yet a mainstream technology for home audio so take all claims with a few grains of salt but if the facts line up don’t be afraid to try if the value proposition works for you.
Also keep in mind better application of technology may equate in general with better performance but even that does not always = better sound. Sound quality will always be very much in the ear of the listener and a fairly subjective thing to determine in the end.