I believe Coded will have some relevance since Nomura said all three games give off story pieces that create KH3, so it has to have some relevance, whether that means it's something big or small i have no clue. But personally if the game is decently priced, and is compatible with my cell when and if it arrives in the US, i will certainly give it a go, course I am also a KH nut, and would probably replace my cell phone just to play it. I think Coded is going to be a fun change of pace to the series, but the real games are going to be 358/2 days and BBS.
I'd be more excited about this game if it was for the DS, PSP, or PS2 because I don't own a cellphone and it's a very bad reason for me to buy a cellphone since this game would be the only reason I have it.