It’s jarring when the bot tells you something will take a “week of work”. A good reminder I guess that it doesn’t have self awareness as we usually think of it.

Yeah, I've seen that, too. In my case it was less about the dev time and more about the regression testing time (much of which would fall on QA and involved reading from external feeds, etc - so, complicated). But your point is fair. The AI is ... notoriously bad at LOE. Not that it's always wrong, but frequently enough (and by a large enough amount) that tradeoffs like that really need humans considering them.