Many languages that don't have these (untagged) union types, usually also have an open issue discussing if/when they'll be added. I've hand several occasions to

Many languages that don't have these (untagged) union types, usually also have an open issue discussing if/when they'll be added. I've hand several occasions to want to use them where the available nominal sealed/enum type of the language is insufficient. In these cases it didn't matter if the components of the union were nominal, only that the union type itself wasn't.