Bitcoin mining is the manner in which bitcoin transactions are processed. Therefore there is no 'wastage' involved. What is being created is of value within the system itself. So long as people trade in it, it is valuable.
The problem most of the people I see decrying Bitcoin seem to have is the irrational and fallacious belief that 'their money' is somehow more intrinsically valuable than Bitcoin.
You can't eat dollar bills. You can't eat gold. You can't eat stock certificates or bearer bonds. Intrinsic value means that in and of itself, the item is valuable. Not: "Because this has had 200 years to build the confidence of people in it's value, people value it."
Should the zombie apocalypse happen, your dollars are going to be worthless. Your gold is going to be worthless. Your knotted cords are going to be useless. Your shells on a string are going to be useless. And yes, your bitcoins are going to be useless. The only people who will accept any of them are people hanging on to the 'old system'.
Currency never had value in and of itself. EVER. It has always been a means of stockpiling imaginary 'value' based on the hope that everyone you deal with will agree to it's value so you don't have to go around trying to pretend to be trapped in an old school adventure game where you have to find a chicken to give to the witch doctor so he'll give you his cure for poison ivy so you can give it to the lady with a clay pot so she'll give you...