You make a better product if you plan it out first. That’s part of a PM’s job so it’s natural fit when the ai does the coding. The code may not be ideal but it’ll have the structure you can improve on.

> You make a better product if you plan it out first.

Maybe. Maybe not. Sometimes you have to see it to understand what's wrong / how can it be improved. It's one of the actual benefits of pre-religious agile - have something in front of your sponsor ASAP, adapt to their feedback. This loop can be made faster, but you'll still need some expertise at every level. Just not so many bodies.

Entire product or a feature for a product? Sometimes you just want to test an idea and vibe coding works well for that in the very short amount of time it takes now. Product market fit, user testing, engineering, those can come after the hunch.