Regarding this:
>Actually most of the energy comes from renewable sources, which would be wasted otherwise. The Bitcoin mining industry is so competitive, it wouldn't be profitable otherwise.
Geothermal energy isn't renewable unless it's used sparingly. Hydro-power requires huge sacrifices of land, usually fertile valleys, in the reservoir lakes. Windmills are loud, huge and ugly. Power lines require sacrifices of land. And everything needs to be produced, with the environmental impact that brings.
I'm not saying renewables are bad, they're not, but they are not so pristine that using them for bitcoins isn't a sad thing.
It's not only black-market commerce though. Porn, legal marijuana, gambling, auctions are for example considered off limits by most payment processors and in some cases even banks. PayPal even froze Minecraft's account (but it was quickly reinstated due to it's popularity, many others have not been so lucky).
Excellent point about renewable energy.
And they can be used for more sensible things than mining crypto.
But that's an argument, which never can be won in discussions with crypto enthusiasts.
An enthusiasm, which, to me, has almost cultish qualities.
That argument is just silly. I don't think that miners give a flying fuck where the energy is coming from as long as it's cheap.
Yet many do use it as a currency, volatility isn't a showstopper. Just look at the use in darknet markets, most serious VPNs and VPS services offer it and you can buy all sorts of stuff on for example Webhallen or Inet (two of the biggest Swedish online computer stores).
> So it's built on nothing, it does nothing and underpins nothing
And this is wrong. It's secured by cryptography and game theory.
The big thing it does is fairly simple: It enables digital payments without a trusted third party. It's relevant for businesses who cannot accept credit cards and there are thousands of stories where startups gets their accounts frozen, for arbitrary reasons, which may tank their business.
I wrote about this and more here: https://whycryptocurrencies.com/
> it wastes huge amounts of otherwise useful energy
Actually most of the energy comes from renewable sources, which would be wasted otherwise. The Bitcoin mining industry is so competitive, it wouldn't be profitable otherwise.
I don't want to wave away the concerns as nothing, because it is a valid concern, but there are tons of other things we waste much more energy on.