Very wholesome chapter and I really enjoyed it ^^.
I think it's pretty obvious than one piece is not what we value as treasure today in gold/money etc. but something else that the ancients regarded as a lot more valuable, but has kind of lost it's value in our world today, which is why I think Roger laughed when he saw it. In which case, like Oda said, that's a pretty massive hint with regards to what one piece is.
With regards to Oden, I suspected as much that the answer at the end of his journey would lead him to the reason why Wano closedoff it's borders and it's probably why he was so hell bent on becoming Shogun after accompanying the roger pirates. However, like with most things in this world, you can't eat your cake and have it. Oden did not only break the iron clad rule of not leaving wano's borders but also returned only to abandon the country again at a time when they needed him the most and also abandoned his family on wano as well in the name of adventure. From a moral stand point, there's not really much to say in Oden's favor and I can't really say he deserves to lead Wano even tho it's his birth right tbf and whilst I don’t think the answer he found on his journey will be compelling enough to make a case for him being Shogun, it’d be interesting to see if it was worth all the risk he took & the suffering Wano endured. This whole theme of adventure trumps everything else (follow your dreams even though you have to abandon everything else is a theme that has been a core part of one piece from the very begining, even yasopp did the same. Can't say I understand it lolz but it's what it is, even tho someone like me would criticize oden for his actions, I get the feeling that the pirates or maybe even the men in the verse won't. All that said, looks like we’re finally nearing the end of the flashback and I’m pretty excited about this bit. What kinda welcome did Oden receive when he finally went home? Did he regret not staying back on Wano 4 years ago? Are both he & Kaidou already acquainted with one another? I mean they are both very notorious Pirates with some sorta relation to WB. Also, this flashback I think presents a very compelling reason for one of Oden’s Retainers betraying Oden in that said Traitor could feel Oden betrayed him first by abandoning him/her & wano as well.
Lastly, Franky mentioning he was abandoned by pirates is pretty interesting. Which pirates exactly & is his dad also a pirate as well?🤔 I personally think it’s interesting coz a Japanese youtuber I follow has been going on about Franky potentially being Kaidou’s son, which I didn’t really think much of till now but well we shall see ^^.