CUs will issue anything that can help their maintain the required returns on the owners of shares (read: you). They can issue loans, but because they are not issuing on speculation but on a clear expectation of a return to the owners of the shares (read: you) they cannot loan as much. Your shares are the dollars in your account, the interest gained is the returns from loans.
These have to be guaranteed by someone, either the NCUA or another CU or bank. In fact, you can go to a Credit Union that doesn’t insure via the NCUA. I wouldn’t recommend it.