> Visa and mastercard together employ ~20k people and handle much, much, much more transactions than all the cryptocurrencies combined.
20K people (debatable) and a bunch of computers and networks which need to be managed by more people, and the infrastructure doesn't run on sunshine either (yet).
Without laboring the point, if your position is: * The methods applied by the crypto currencies waste more energy than our current system of currency.
I'll accept this, iff we make sure we've collected data rigorously and we notice that the difference is significant. Even then, there's no reason to give up on the idea of crypto currencies, we just have to make it more efficient.
Proof of work systems (such as bitcoin and ethereum as of now) inherently cannot be made more efficient - their security requires that approving transactions must take so much computing power that an attacker can't afford to burn as much resources as they'd need. It'd be trivial to make the processing 100 or 10000 times more efficient, but that would defeat the whole purpose - instead, the computational (and thus energy) requirements must grow as the currencies become more valuable and processors more affordable; that's why we have the scalable difficulty factor in bitcoin etc - so that the mining gets less efficient with time.
Visa and mastercard together employ ~20k people and handle much, much, much more transactions than all the cryptocurrencies combined.
The EU SEPA customer payments system handles ~1000 times more transactions than ethereum, and the infrastructure for running that (spread across all the involved banks) likely takes thousands of people, but not 200k, and certainly not the 200 million people that would be required to do so as horribly inefficiently as cryptocurrencies do.