I find it interesting in this chapter, Oden explicitly hypes up his sword fighting ability. On his admission, his two sword style is the best there is. It's good to see, that actual sword technique and style still holds weight.
Is this Oden claiming himself to be the best swordsman at that period of time? This was likely after he already knew Roger had passed away too.
Also on a sidenote, lol at people who say Oden is not a benchmark for Zoro to surpass. Not only has he inherited Oden's blade, but Oden's two sword style has been called the greatest.
Perhaps Hiyori seeing Zoro use the 3 sword style had a huge sway on her deciding he was worthy of taking Enma.