[Rjevski]

Because I have yet to find an actual legitimate use-case for a blockchain. Every task in our modern business world actually requires a central trusted authority.

Edit: not to mention that mining is an incredible waste of time and energy that can instead be put to good use.

[Rmilb]

Good use is subjective, plenty of people are using the blockchain as a speculative asset and willing to pay transaction fees for it.

[gwbas1c]

It's a great way to hide a pump-and-dump scheme. Although blockchain is a legitimate undertaking, if you're good at surfing hype, you'll know when to get in, get out at a profit, and then leave all the other suckers holding worthless bitcoin.