I know of no review process that produces the same level of understanding as does authorship, because the author must build the model from scratch and so must see all the details, while the reviewer is able to do less work because they're fundamentally riding on the author's understanding.
In fact, in a high-trust system, e.g. a good engineering culture in a tech company, the reviewer will learn even less, because they won't be worried about the author making serious mistakes so they'll make less effort to understand.
I've experienced this from both sides of the transaction for code, scientific papers, and general discussion. There's no shortcut to the level of understanding given by synthesizing the ideas yourself.
In fact, in a high-trust system, e.g. a good engineering culture in a tech company, the reviewer will learn even less, because they won't be worried about the author making serious mistakes so they'll make less effort to understand.
I've experienced this from both sides of the transaction for code, scientific papers, and general discussion. There's no shortcut to the level of understanding given by synthesizing the ideas yourself.