I agree with you that AI has much larger theoretical benefits than cryptocurrency, but I don’t think it’s fair to say cryptocurrency is wasteful by design. Bitcoin’s proof of work serves a vital function: securing the network from double-spending attacks. At the time of bitcoin’s invention, it was the only known solution to that problem, so it’s no more “wasteful by design” than a bank hiring a security guard. There are admittedly alternatives to proof of work today; I’m unsure how well they work by comparison, but even if they suffice for security, that only means that bitcoin is wasteful due to being more primitive technology, not by design.