I have seen good, dispassionate, defenses of blockchain tech pop up in the comments here, but this argument has played out many times and it probably wears on people.

Anyway, Namecoin seemed like a pretty nice use case, even if it didn't take off. Smart contracts seem like a good idea to me. Behind all the hype and idiotic money chasing behavior and criminality there are some niche but proven-useful technical innovations. And despite people throwing blockchain-everything at the wall to see what sticks for some time, there's still plenty of opportunity for new applications to emerge.