Imagine this:
Oda, in a SBS, says that, I don't know, Imu has blue hair.
That becomes "canon". but never appears in the story.
Later down the line, he changes his mind and when Imu's is revealed, his hair is green, not blue.
What now?
"Canon" is a BS concept used for the sole purpose of pushing some agendas when it's convenient.
Manga =/= Anime.
Authors can't bend reality, change concepts as they see fit and make a mess out of things just because "they are the authors".
That's not how fiction works and it often is used purely for fan service, indicating an incapacity of creating a solid enough story and coherent elements.
Just look at JK Rowling's tweeting madness.
Oda, in a SBS, says that, I don't know, Imu has blue hair.
That becomes "canon". but never appears in the story.
Later down the line, he changes his mind and when Imu's is revealed, his hair is green, not blue.
What now?
"Canon" is a BS concept used for the sole purpose of pushing some agendas when it's convenient.
Manga =/= Anime.
Authors can't bend reality, change concepts as they see fit and make a mess out of things just because "they are the authors".
That's not how fiction works and it often is used purely for fan service, indicating an incapacity of creating a solid enough story and coherent elements.
Just look at JK Rowling's tweeting madness.