If you opt for non-human-readable wire-formats it better be because of very important reasons. Something about measuring performance and operational costs.

If you need to exchange data with other systems that you don't control, a simple format like JSON is vastly superior. You are restricted to handing over tree-like structures. That is a good thing as your consumers will have no problems reading tree-like structures.

It also makes it very simple for each consumer/producer to coerce this data into structs or objects as they please and that make sense to their usage of the data.

You have to validate the data anyhow (you do validate data received by the outside world, do you?), so throwing in coercing is honestly the smallest of your problems.

You only need to touch your data coercion if someone decides to send you data in a different shape. For tree-like structures it is simple to add new things and stay backwards compatible.

Adding a spec on top of your data shapes that can potentially help consumers generate client code is a cherry on top of it and an orthogonal concern.

Making as little assumptions as possible how your consumers deal with your data is a Good Thing(tm) that enabled such useful(still?) things as the WWW.