Are products that pay principal and interest, such as bonds or ELBs, covered by deposit insurance?

No. The Financial Supervisory Service advises that bonds, unlike deposits and savings, are excluded from deposit insurance.

Derivative-linked bonds (ELBs) are also not covered by deposit insurance even if designed to pay back principal and interest, so if the issuing securities firm goes bankrupt, you may not get your principal and interest back. Even if a product is described as being of the 'principal-and-interest payment type', check separately whether it is protected.