UN: https://www.youtube.com/watch?v=WUY4CV50VQo
You're right that mercury metal isn't a such a big problem. The problem is that people are heating it and breathing the vapours.
[0]:https://www.amazonconservation.org/pdf/gold_mining_fact_shee...
https://www.japantimes.co.jp/news/2017/02/01/national/tokyo-...
[0] https://www.gold.org/about-gold/gold-supply/gold-mining/how-... [1] https://www.statista.com/statistics/299603/gold-demand-by-se...
Gold plating contacts may have been necessary with analog back in the day, but today's digital equipment is much more reliable thanks to error checking / correcting protocols, and other improvements. Besides, gold contacts wear out faster.
Amazon basics: https://www.amazon.co.uk/AmazonBasics-Male-B-Male-Cable-Feet...
Anker: https://www.amazon.co.uk/Anker-2-Pack-Nylon-Braided-Tangle-F...
Unnecessary if you ask me... It's more like jewellery rather than a cable :-)
Zinc / aluminium is probably a better combination for USB, as it's more durable.
https://www.ebay.co.uk/sch/i.html?&_nkw=awg%20%22gold%22%20u...
I guess they'd hold up better in a damp environment.
https://www.ebay.com/b/Gold-Leaf/41369/bn_55209815
I bought 2 sheets ($0.99) out of curiosity. They are so thin and fragile that they ball-up with the slightest "breeze".