Work is what makes entropy useable. It's through work that we can assert objective truth. It's certainly 'wasteful'. But, so too is gasoline.
Huh? Exponentially? The difficulty level is rising exponentially, but that's owing to continued investment in specialized hashing hardware. I certainly don't think that the actual amount of electricity being put into hashing is still growing exponentially. It would only grow exponentially if the price of Bitcoin continued to appreciate exponentially, and that hasn't been the case in years.
Gasoline at least gets you from A to B. Burning cycles is much more wasteful. Bitcoin's proof of work/waste is really something like 'I can prove that it is statistically likely that I wasted a shit-ton of power heating this data centre, doing SHA hashes, trying to find one that has a high number of leading zeros.' That's pretty wasteful IMO.