Paying bills might be the furthest thing from our minds in prepping. But if electricity is out, we can't email money, send Paypal, and we might not even be able to call offices to negotiate late payments.
Home property can quickly go into foreclosure if mortgages are not paid -- but also, if tax bills are not paid. Towns can be lenient, but if everyone defaults at once during an event, the town cannot meet their own expenses. So we will need to make sure all property taxes are paid on time.
Stamps. I use them now for holiday greetings, and barely succeed at that. If phones and internet are disabled, we will need stamps (and checks) to send out bill payments. Stamps/envelopes will be handy for contacting family and friends, letting them know where we are. Sounds ridiculous, but extreme events bring extreme vulnerabilities. Whether mail carriers will still work, will depend on the event and region.
Stamps can also be gift and bargaining items, since there will be others who need them. They barely take up space, holding value-- keep them waterproof.
Compare how $50 in stamps takes up less room than $50 worth of other valuables. Home robbers do not steal stamps (unless displayed like a collection).
There might be bills that can be paid ahead, especially if you see trouble coming. Autobilling puts liability in the hands of the company, ideally, but that could change. So if there's anything you absolutely want to hold onto, make sure it's covered.