@Alekezam congratulations on successful interview! Glad it went smoothly.
In my opinion, there's no harm or downside for asking for it. It's also free 🙂 I've seen only N-400 being conducted with "decision cannot be made" outcome. This is a recommendation to minimize chance of combo not happening.
By law IO could have asked for more documents. It's better be safe than sorry. A lot of the times, those documents are generally good to have for other life situations. Sometimes US citizen loses their certificate of naturalization or birth certificate. They may not be asked during I-751 / N-400 combo, but they can be vital for other things.
Either way, good to hear your story, thank you for the details!