Not OP, but I think it's not about producing value now, but how much it will cost in the long term. If you have unmaintaable code that is N times larger than a hand-written codebase, what is the cost to be?
Its about the team being able to review the code to tell if its slop or not. It's hard to meaningfully review huge changes to a codebase for one PR. Just imagine if there are 5 PRs a day with 1000+ insertions. It leads to the production codebase being somewhat of a black box imo