This is only a small piece of the story for what people say when they want tagged unions. Without all of the ancillary support in the language, like exhaustive pattern matching, it really doesn't count.

That is a LOT of code (very ugly code, I would add) that could be replaced by `type Float = float32 | float64` in a language with actual support for union types.

The C++ committee said the same thing, and gave us std::variant. They are painful to work with and do not really deliver most of the benefits people want.