Whether you keep all your money in your own house or lend it to your neighbors doesn't make a difference if a passing army can pillage and burn everything in yo

Whether you keep all your money in your own house or lend it to your neighbors doesn't make a difference if a passing army can pillage and burn everything in your town. What's different is that the modern legal apparatus make it much easier for you to track down someone who defaults on a loan and force them to pay you back. Just petition a magistrate, and he can magically transfer a portion of your debtors' income to your vault every month no matter where they live!