I dont see how anyone would think that keynesianism has been useful. And more importantly economics is supposed to be a science, so it should be correct not useful and keynesianism has been proven false again and again.

I tried having a debate with some keynesians who were claiming Bitcoin would not succed because keynesianism and they could not handle it, so I extend the offer to you. But by debate I dontmean an internet slogan-catchy phrases ridiculous back and forth, I mean an honest exchange of ideas.