Money belts are a practical, possibly essential item when travelling. Yvette and I took different varieties of money belts on our most recent trip.
I had one of those that hang from your neck and tuck underneath your clothing. I chose this variety because I was doing all of the driving and did not want the discomfort of having a money belt wrapped around my waist all the time. The one I chose was spacious enough for 2 passports, tickets (e.g. train tickets), cash and a few other bits and pieces without being too bulky.
Yvette had a waist money belt, and she was able to fit much the same sorts of contents in it. We each had our own passport plus one of the kids' ones so that if something happened to one money belt we didn't lose all four at once!
Problems emerged within days of setting out. The cord on my money pouch had a toggle thingy with a small spring inside it so that the length of the cord could be adjusted. The spring snagged on the cord and almost shredded it completely through - before we'd even reached a destination. We had to take the toggle off and tied a knot in the cord at the required length to make do.
Yvette's developed a hole, caused by wear from the corners of the passports within a week of use. Luckily she can sew - because no matter how much she kept closing up the hole the passports would soon open a new one. Money fell out at one stage - luckily we probably only lost a few euro coins, but it was annoying all the same. The passports seemed to be putting too much pressure on the fabric seams and they kept separating.
While in Spain we encountered very hot weather. Yvette found that her money belt became irritating against her skin, making her itchy and sweaty. It was heavenly relief to take it off when we got back to our room! My money pouch wasn't so bad in terms of irritating skin, but it is more annoying to access when you need to, and it does hang like a lump around your neck. If you let it hang loose under your top layer it tended to swing back and forth, so I found that I had to tuck it into the waistband of my pants to keep it still.
Personally, both the money belt and the money pouch needed a better design. They are safer than having a more easily accessible wallet or handbag, and they are designed to carry slightly larger items like passports, but they were not a huge success. We will be investigating alternatives for the next trip.