TOEI follows the manga pretty accurately, there was no substantial point in rolling with surprise mode when that was pretty much already spoiled. It would have only worked for the people who don't follow the manga accurately or don't follow it at all and only watch the anime.
Like, even in the manga, its not a surprise that Oden cuts Kaido. We already know this to be the case. In fact, that's precisely what's revealed in the chapter being adapted.
Removing all context behind the cut, while showing the cut itself, gives them the chance to visualize how powerful Enma is, while only giving a broad idea of the circumstances in which Oden cut Kaido.
Like, I think that Enma cutting Kaido is going to be revealed next episode, so I would hardly say its a massive spoiler.