What's the benefit of delaying typing? By typing it at ingestion, you guarantee that invalid (with respect to structure) untrusted data will not break your code

What's the benefit of delaying typing? By typing it at ingestion, you guarantee that invalid (with respect to structure) untrusted data will not break your code down the line. Doing otherwise means that you're manipulating untrusted data with a strong risk of forgetting that it is untrusted. I have seen large applications (think hundreds of millions of daily users) break because of such oopses.