I really struggle to see how it's useful to an ordinary person. You maybe save a little money, sure, but for a non-1%er the risk just seems completely disproportionate. I mean any dealer/business would accept a bank transfer, right? So it only makes sense in the first place for buying a car person-to-person (and for friends/family a bank transfer would work too). Carrying 30k to meet a more-or-less stranger who knows you're going to be carrying 30k? Sheesh.