Must you? - No. I don't remember any questions about/containing morse in the IMC written.
Should you? - It does help identing beacons which use morse, and if you wanted to do a JAA-IR you'll need it. It may also "help" you impress the IMC-examiner (flying) when you notice a particular nav-aid is on "test" (by the ident) because you didn't notice that in the NOTAMs...
Can you? - If I can, anyone can
