Having a cash fund at home can be of a great help for the short period when you may not have access to your bank money.

Natural Disasters
Large-scale natural disasters such as hurricanes, earthquakes and tidal waves can mean that there is widespread damage to the power infrastructure.

If this happens, all the retailer machines that accept credit cards will be down as well as ATM machines to get money out. People selling supplies will rarely take credit cards during these times and having a stash of money can make it a lot easier to find someone willing to help you escape the predicament. During a natural disaster, cash is often king and another reason you should always have some at home.

Stolen or Lost Wallet
If you wallet gets lost or stolen it will take time for your credit cards and bank cards to be reissued. If it happens to be during nonbanking hours, you may not have any way to gain access to money. 

Credit Card Troubles

With more and more people defaulting on their credit card debts and banks already reeling from the mortgage meltdown, banks have been reigning in the limits that they offer on credit cards. While not likely, there also can be instances when your credit cards get frozen.

If you count exclusively on your credit card for purchasing, any trouble can quickly find you without a money source until the issues are worked out. Having money at home can help you get by while these issues are being resolved.