Forest fires if you live near wooded areas or even just a house fire, flooding if you live in low areas, chemical spills if you live near a plant. There are certainly some very real world scenarios that would force you to leave your home, it doesn't need to be a global catastrophe. Having a bag with a few items that will make the following few days a bit easier is not a crazy idea, cash is probably the single most important thing to pack in any of these scenarios.