KOReader: ePub vs kepub, technically speaking

The differences of ePub vs. kepub format on a stock Kobo has been debated ad nauseam, and is not what I'm asking here...

Is there a technical superiority between the formats when it comes to KOReader? Does KOReader just strip out and ignore the added spans from the kepub formatted files? Are there any specific KOReader related technical benefits for either format?

I had been converting all books to kepub via Calibre, but now I'm wondering if I'm wasting my time, since KOReader is significantly preferable to the native rendering engines (ePub or kepub) for my taste. Is there a reason to not just leave everything in ePub format if I have no intention of using the stock reader software?

Thanks.