The special purpose revenue bonds issued pursuant to this part shall be and are declared to be legal and authorized investments for banks, savings banks, trust companies, savings and loan associations, insurance companies, credit unions, fiduciaries, trustees, guardians, and for all public funds of the State and its political corporations or subdivisions. The special purpose revenue bonds shall be eligible to secure the deposit of any and all public funds of the State and of the counties or other political corporations or subdivisions of the State. The bonds shall be lawful and sufficient security for these deposits to the extent of their value when accompanied by all unmatured coupons pertaining to the bonds.