Zero Percent Certificate of Indebetness as an investment

In what investment situations would you use the Zero Percent Certificate of Indebtedness (C of I) account in Treasury Direct? Tom's response The Zero Percent C of I isn't meant as an investment, but just as a temporary holding area for money you have deposited into your TreasuryDirect account. You can move money into a C of I from a payroll savings plan or other type of scheduled investment or by redeeming a Savings Bond. You can move money out of a C of I by buying a Savings Bond or making a transfer to your bank account.