It is mentioned, but there's not a lot of detail. This seems to be the juiciest paragraph concerning the actual business:
All told, less than 1 in 10 second-hand-goods sellers didn’t deliver as promised. That was good enough for Mitsumoto, who relaunched the service, called Cash, in August as a new way to gather inventory for an online flea market. Total daily purchases are capped at 10 million yen, and are limited to smartphones, luxury handbags, watches, clothing and other specific items from a list of several thousand. Customers take a photo and are given a non-negotiable offer. Prices are set automatically based on data gleaned from other second-hand marketplaces and Cash makes money by reselling the goods.
Even if they didn't, it attracts a lot of customers to their second hand store where they don't "have" to sell the used goods but can sell new stuff with a (predictable) margin.
All told, less than 1 in 10 second-hand-goods sellers didn’t deliver as promised. That was good enough for Mitsumoto, who relaunched the service, called Cash, in August as a new way to gather inventory for an online flea market. Total daily purchases are capped at 10 million yen, and are limited to smartphones, luxury handbags, watches, clothing and other specific items from a list of several thousand. Customers take a photo and are given a non-negotiable offer. Prices are set automatically based on data gleaned from other second-hand marketplaces and Cash makes money by reselling the goods.
Granted, it is a bit vague about the reselling.