> Don't you need to write your own fair share of code

Do you need to be good at making films to be a good critic of films? (Roger Ebert)

Do you need to be a great chef to be a Michelin reviewer or food critic?

Do you need to be a great singer to be a good judge of musical talent? (Simon Cowell)

I think you can tell if some output is "good" without being expert at the doing part. You need to understand the domain, the inputs, the outputs, the range, but not necessarily be expert at the doing part.

In fact, many, many more of us can tell "this book is good", but relatively few of us could write a very good novel. We have a sense that "this show or movie is entertaining", but few of us could produce one!

One of the teams I worked with, our support engineer was extremely adept at reading code. He would trace defect reports to the lines of code and write excellent tickets that deeply understood the root cause of the error because he had a good conceptual model of the design and he was skilled at reading code. However, when it came to fixing the error, he had no clue!