Why would SHEIN be getting into selling used books from small sellers via Allibris? Tariff related?

Today my book selling community reported that many who are selling on the used book site Allibris has been getting huge international orders.

the partnership announcement: https://www.publishersweekly.com/pw/by-topic/industry-news/bookselling/article/99104-shein-expands-into-bookselling-with-alibris-partnership.html

the community confusion (booksellers):

https://www.reddit.com/r/BookCollecting/comments/1q6xoo1/comment/nycwiy6/?context=1

This is an extraordinarily weird, non-aligned and very low margin market for SHEIN to get involved in. Do any of you have any insight into what the rationale might be? I can’t imagine it’s NOT tariff related but who knows—maybe in Chiba there’s a huge market for english used books???