But the AI coding agent can then ask you follow up questions, consider angles you may not have, and generate other artifacts like documentation, data generation and migration scripts, tests, CRUD APIs, all in context. If you can reliably do all that from plain pseudo code, that's way less verbose than having to write out every different representation of the same underlying concept, by hand.

Sure, some of that, like CRUD APIs, you can generate via templates as well. Heck, you can even have the coding agent generate the templates and the code that will process/compile them, or generate the code that generates the templates given a set of parameters.