- I don't have to worry about 6,500,000,000 people having access to my house. At most, there is a market of around a million or so who would live in close enough proximately to me.
- I don't have thousands of people across the world tapping on my windows to find out how easy they are to break into.
- I'd trust the chances of a local thief being caught more than a hacker across the globe stealing BitCoins being caught.
I could go on and on.
Right now, the BitCoin landscape is like the Wild West, probably even worse. Systems simply aren't in place to really protect people, and you have the potential to steal from anyone in the entire world.
In real currencies, we have systems in place to protect holders. In the U.S. we have the FDIC, which insures bank accounts up to a certain amount. This insurance incentives people to keep their money in banks instead of the house because it's safe (both physically safe from theft and safe from bank failure). My understanding is that there are BitCoin "banks" but there is nothing guaranteeing these deposits. There are also established systems in place to help prevent theft. Police departments, close physical proximity to others (neighbors being able to see odd activities), etc. to prevent thefts.
But if you have banks that store Bitcoins for you, then you're trusting their security processes, not your own. We don't have Bitcoin banks yet. For BC users, maybe that's worth looking into.