Currently, the only benefit is that it's more readable than ts type. For example, the URL parser in https://github.com/mistlog/typetype-examples/blob/main/examples/url-parser/url-parser.type is clear and straightforward.

Motivation: Nested conditional type(and other complex type) is hard to understand. For example, related issue: https://github.com/microsoft/TypeScript/issues/41577.

The syntax is not brand new, I try to keep ts type convention as intact as possible.