But that's only really relevant in the last layer, the backend-for-frontend pattern; as an organization or domain expands, more layers can be added. e.g. in my current job, the back-end is a SAP system that has been around for a long time. The Typescript API layer has a heap of annotations and whatnots on each parameter, which means it's less useful to be directly used in the front-end. What happens instead is that an OpenAPI spec is generated based on the TS / annotations, and that is used to generate an API client or front-end/simplified TS types.

TL;DR, this value prop is limited.