When creditors charge off accounts, they're declaring it as a loss and writing it off on their own taxes. As a result, the creditor might owe the federal government a little less. You, however, are still responsible for repaying the debt. The creditor can still attempt to collect on the debt and might even hire a third-party debt collector.
Charge-offs are typically more difficult to repay because the creditor, at that point, requires you to pay the balance in full. You no longer have the privilege of paying the balance over a period of time. You may, however, be able to break up the total balance due into two or three payments, but you won't get the convenience of paying over several months.
It's also important to note that paying a charge-off doesn't remove it from your credit report. Instead, the charge-off will run the full credit reporting time limit unless you can negotiate a pay for delete with the creditor.