The lack of rigour around the specifics of the idea, the tech or maths behind it, etc. is not new or unique to crypto VCs (look at some of the nonsense that gets funded!). What’s more unusual is that anyone can often read the same papers and look at the code and decide the idea is dumb/illegal/won’t work. We can’t usually see what it is that made the VC invest, though.
But sure, if you’re looking for VC funding as a signal of great tech or an obvious market need or problem being solved, you have to at least be really picky about which VCs you follow and how much you read into their pronouncements (some are surely better than others, though).
Also, those projects that do have good tech and a viable product/solution will almost certainly benefit from the support of top quality VCs.