Yes, they may be "burning up planetary resources" - but you need to look at the big picture. First of all, not using electricity in this day and age is impossible, so you can't complain that some new technology uses too much planetary resources - you need to go to the source of electricity and complain that we are burning coal/etc. instead of using wind and solar. I think you would have a lot less to contemplate if all bitcoin farms were powered using solar panels and turbines. Secondly, the amount of electricity used for bitcoin pales in comparison to the waste from other sources which have far less pleasant effects on the world than bitcoin.