Just like digging out gold, it seems the labor wasted are unnecessary, but it does solve the origin of value problem: The man who create money must pay fair price to get it, otherwise everyone will be just creating money and no one will be working
Originally PoW was used Satoshi as a way to roll a lottery and to protect against a Sybil attack. Later, Bitcoin holders created a myth that resources must be wasted to give value to bitcoins (is anyone surprised by such their behavior?
)Any limited resource can work as a protection against Sybil attacks (this is called resource-testing). In PoS available balance is used as such the resource.