Bulbapedia, a community-driven, online Pokmon encyclopedia, indicates that the Expedition Base series was slated to be released in May 2002, but it was delayed to September so it could be introduced at the same time as the Nintendo e-Reader
The rewards increase in-line with the finishing position of the player
Its also a fast-beating creature thats easy on the mana and can dole out some damage before shields are fully raised
While ordering lots of things at once will temporarily slow down the frame rate of even the hardiest of computers, having plenty of boxes ready to open makes things a little more efficient
Sure, you can represent a 1/1 Soldier with a die, a coin, or a Hot Cheeto if it's a Red Soldier, but actual tokens just make the game cleaner
Either way you get a menace creature that pops a threat on ETB