(a) An issuer or nominated person has a security interest in a document presented under a letter of credit to the extent that the issuer or nominated person honors or gives value for the presentation.
(b) So long as and to the extent that an issuer or nominated person has not been reimbursed or has not otherwise recovered the value given with respect to a security interest in a document under subsection (a), the security interest continues and is subject to article nine, but:
(1) A security agreement is not necessary to make the security interest enforceable under section 9-203(b)(3);