All technologies are grifts when controlled by the capitalist class and marketed under the logic of capitalism. Simple as that. Even the simple hammers you find at a hardware store are a side effect of some rich asshole's money hoarding operation.
For this reason, I do not reject the listed technologies outright. (Although I do not personally know of a non-capitalist use for Blockchain, I'm open to suggestions.) I reject the capitalists who control these technologies.