It is equivalent in the amount of information you can encode, but not in how you can use it. Classical example is wrapping multiple times: Option<Option<one |

It is equivalent in the amount of information you can encode, but not in how you can use it. Classical example is wrapping multiple times: Option<Option<one | two>>. If you have null | null | one | two, well... that just boils down to null | one | two.