there's one hell of a difference between a large financial organisation or an exchange and some half arsed startup who hacked up a web site in PHP that just happens to handle something that represents a currency. The former at least probably has a QA team, knows industry regulations and best practices and designs their architecture properly. Oh and they have cumulative experience and a designated location you can visit with burning torches and pitchforks when they steal your money. I'm ignoring regulation as I've worked in the compliance industry and it's entirely about working around it.
Not joking and I'm sure that this is going to stand on a few toes but some of the stuff I've seen on HN is verging on criminal. So many immature poorly thought out and damn right dangerous products being thrown out. Lots of people are sitting on ticking bombs like this.