Yo so I saw this for sale at a game store in town. Full Japanese version going for $120 AUD and people were buying it in fucking DROVES. Like, not just 'oh cool it's in stock' people were like CREAMING THEMSELVES to buy/play a very overpriced game completely in Japanese that I am betting 80% of them won't even understand.
It's just like, jesus, people. why??
You are asking why, but you just explained it right there.
It doesn't have to be any sort of worthwhile game, people don't buy it for the experience of actually playing the game. They buy it just for the experience of buying the game. To put it simply: they have to all go in at the same time and buy it in droves right at that moment or else it wouldn't be something they all wanted in the first place.
I know that doesn't make any sense, but I've abandoned trying to explain Final Fantasy in any sort of rational or sensible manner ages ago.