>>2758446Not to mention fitting the whole line into one screen. I'm assuming this is Chocobo Mystery Dungeon on the Wonderswan? There wouldn't be enough space on the top line to write out 冒険 as ぼうけん.
And besides, if you're going to bother to create graphics for kanji, then it would make more sense to make it for something you can use over and over again just on one screen (as 冒険 is here) than it would be to only use kanji graphics once on screen (as 新しく would be). Not only that, but if the player didn't know the kanji for ぼうけん then this would quickly teach it to them. They just ask their older sibling or parent or teacher or whoever what this kanji is, get the response, and immediately they get it re-enforced multiple times just on one screen, and no doubt many more times as the game goes on.
So in short, I'd say they went with the kanji that they did because it was most efficient, most effective, and most educational.