1) The basket seems (intentionally?) limited in volume, perhaps discouraging the purchase of jumbo buckets of popcorn and large drinks. Compare to the American tray-style carrier: flatter, with less restriction on the girth of purchased items.

2) The basket is a “generic” storage device, irrespective of what you’re going to put in it – there is no visual cue as to what you’re supposed to buy, or what the clerk is supposed to sell you. Compare again: the American tray-carrier is molded to accommodate four beverages and an additional upsell item, like a pretzel, nachos or candy (assuming your bucket of popcorn, intentionally too big for the tray, will be carried separately).

3) Are the floors in theaters not sticky (a) because Japanese people are cleaner than Americans, (b) because the trays are a convenient receptacle in which to gather trash, or (c) because the collection of the baskets outside of the theater is a wa way of socially pressuring people to pick up their trash (i.e., “I know you didn’t come in here with an empty basket…”)

I’m kind of surprised they don’t make you sort your trash into different baskets…