You shouldn't try to use every weird dedicated character Unicode has. Usually they are included for full round-trip compatibility with other encodings. (like Ω

You shouldn't try to use every weird dedicated character Unicode has. Usually they are included for full round-trip compatibility with other encodings. (like Ω ohm sign vs Ω omega which is preferred). About Roman numerals Unicode standard says: For most purposes, it is preferable to compose the Roman numerals from sequences of the appropriate Latin letters.