Sounds like a money spinning product for the banks to me. . If you're very careful about shredding all your unwanted personal documents, utility bills, etc. including envelopes bearing your name and address, not disclosing your pin numbers and passwords, and being careful about how and where you withdraw money from cash machines, you'll make it a lot less easy for anybody to steal your identity in the first place. Also, don't belong to networking sites like Facebook and disclose details of your first school, birth date etc, and conmen scan these kinds of networking sites look for personal information to steal.
Before you take up your bank's offer I'd read the Terms and Conditions and see exactly what you're covered for. I bet they don't cover you if your credit card gets cloned, for example.