As I said, I hoped I could think of some use for these hash machines. Same for the blockchain tech itself, i.e. some usage that would not be completely replaceable by some less compute-intensive tech.
I honestly hope those usages exist. I really do. But now I don't think they do.
But, frankly, even for Internet itself everybody could see the benefit quite early.
Anyway, if you do find interesting uses that are not replaceable by simpler things, you would save a lot of garbage!! And thus would do a favor to the environment.
A Classic quote from Paul Krugam indicates that quite a few smart folks, so not everybody, did not see the internet’s benefit quite early or even much later.
Assuming you work in tech, you must be aware how similar attitudes existed (within tech, as well) about what the internet itself would provide.
How are you so certain that:
A) you understand all the possible directions a new, network-effect driven tech could take in its applications
B) none of them add value to humanity
C) there are no parallels in your statement to "well horses work fine, why do I need cars."