Interesting question. I use a typical money belt that goes around my waist, under my clothes, that I literally wear every minute that I am not in the shower. So many are having issues with pick pockets, getting things stolen from backpacks while they sleep, etc. My belt has a larger opening for passport and bills, and a smaller one for credit cards and coins.
I wore that kind of money belt when I was spending six months backpacking around Europe and the Middle East as a teenager a few years ago. But then I was carrying all my money for the six months with me (in the form of travellers cheques).* For those in the audience under a certain age, travellers cheques were backed by the bank allowing them to be spent more or less like cash, but if they were lost or stolen, you could recover the money (although not until you returned home, I think). I
really didn't want to lose them all.
On Camino, I am carrying a lot less money. I'm willing to take the risks rather than reach inside my waistband every time I want to buy something.
*As a side note: It was signing those six months worth of travellers cheques all at once that turned my once legible signature into an illegible scrawl.