My take is that the main difference is the approach to problems the coding agents have. They optimize towards presuming a fully working invocation environment, yet checking everything anyway, and then rolling back any changes and re-testing that such changes worked. Which is great for normal types of software but incredibly tedious for anything aimed at less than a fully hands free automated environment.
In other words, AI is very awesome at scope creep of assigned problems and targeting the validation prompts baked into the review system.