Earlier quoted context omitted.
ASICs have a hardware hash/watt race issue that GPUs (with memory hard algos) don't have (older GPUs are actually more ROI efficient). GPUs are also easier for a wider range of people to get with a much lower cost of entry. I'd argue that GPUs are still a better solution than ASICs, but this is an age old battle full of opinions. Bitcoin hardware isn't worthless for any other application, any other sha256 based netwo…
What's that attack cost supposed to represent? Just the electricity? Seems like a misleading comparison, to get into a position to be able to do this you'd need significant investments in specialized hardware for the likes of Bitcoin and Ethereum. I've seen estimates of multiple billions of USD. And keep in mind that should the attack be discovered, which with coins running on open ledgers seems likely sooner rather…
The problem with that is that the rental market is an open bid supply/demand market. The second you start to rent out enough hashrate, the rental price also increases. That isn't factored into the numbers.
You are correct that the cost of capex/opex for ETH/BTC is in the billions, which is also what makes them so secure and attacking the network would also destroy the network. It is a brilliant feedback loop.