Merchandising in Japan is a powerful force, with a much stronger presence overall than in the States. You can buy licensed goods in retail stores, try for one kind of exclusives in a game center crane machine, or take a chance on a different set of exclusives in a kuji. Even movie theaters have their own exclusive merchandise, and in true Japanese form, the wearable/replica items tend to sell out almost immediately.
For example, I couldn’t get anything but a simple booklet for the movie 君の名は。because the movie had been so popular and I waited too long to go. The same applied for Fantastic Beasts; the replica of Newt Scamander’s scarf was quickly gone, almost certainly due to low supply. Over the next week, I called something like fifteen theaters until I found one all the way in Yokohama that had one scarf left. It was a little bit of an adventure, going deep into unexplored Kanagawa, requiring a platform change, a station change, and a modest walk.
The good news is that the theater in question doesn’t seem to do much merchandise business, meaning I can try them first it I ever lose out on something I want; for example, they actually had a small measure of Kimi no Na ha stuff left over (though nothing I wanted) in addition to the last remaining scarf.
The best news, though, is that I now own that scarf.