>It still expends resources, but does so in a non wasteful manner.
And this is a flaw. There is a law of conservation at work here, whereby to create one source of value, another has to be destroyed. You can't destroy that first source "in a non-wasteful manner". It's not actually destroyed in that case and you've effectively double-spent it and cheated the system in a way that has subtle ramifications on the incentives and security. Even in blockchain, incentives matter and there's no free lunch.
And this is a flaw. There is a law of conservation at work here, whereby to create one source of value, another has to be destroyed. You can't destroy that first source "in a non-wasteful manner". It's not actually destroyed in that case and you've effectively double-spent it and cheated the system in a way that has subtle ramifications on the incentives and security. Even in blockchain, incentives matter and there's no free lunch.