Jonouchi got Mai to take her star chips, also Kaiba used cards to stop guns wow. Still in comparison to the anime he was much more badass here, and not to mention the way he got to the island made more sense as well.
But will have to agree with the upper post, watching the anime and reading the manga simultaneously myself, it is like experiencing two entirely different stories. Sure they share the events, but so much things have either been left out or changed that it makes them totally opposite in tone and intent.