Are custom silver cables or copper cables worth the money or is it a joke ?
Depends entirely on what you’re after. Convenience? Looks? Sound quality? Most of the replacement / upgrade cables sold over at aliexpress I’ve found to be very good (KBEAR, Yinyoo, Tripowin etc). Other cables I’ve found to be superb and practical, like Hart Audio with his multi-kit system.
Then you go into the likes of Norne, Moon-Audio, Lawton etc. You’re paying for premium components with pretty weaves (and the craftsmanship / time). Functionally speaking I’d they’re just about as good as any of the 20-30 dollar chinese cables. This is my opinion after having used everything from literal power cords to Abbey Road Moving Air cables for $1600.
I’ve had Moon Audio Silver Dragon for my HD600’s back in the day, was the cable a step up from the stock cable? Hell yes. Was it worth the cost? Probably not, since the soldering broke twice on the connectors and then they broke a third time later on and I couldn’t be arsed sending the cable back for yet another repair job. But the cable did give me some enjoyment over the years, I just didn’t want to continue spending on it as I was paying pretty much more for the cable than my headphones.
So yeah, your mileage may vary. Put your money where it’s worth, go for something that ticks your boxes.
Also welcome to HFGF!