The name “in between” really stands for this: the founder of Eslite firmly believes that humanity/arts and business can coexist “in between”.
The business model of Eslite is rather interesting: the bookstore portion is often money losing (Eslite famously “lost” money for 15 years”, with the co-founder of Asus Tzu-Hsien Tung famously continued pumping money into Eslite for the Eslite founder’s initial ideal). But the bookstore itself is meant to draw people in. As Eslite matures, it gradually becomes a real estate company rather than simply a bookstore: this business model is akin to JR East’s (very successful) business model, or the old model of American suburban mall using department stores as anchor (or in recent years, using grocery stores as anchor) to draw people in, and in return rent the remaining stores to other shop keepers. Eslite uses humanity to sell traffic, in essence. Just like JR East uses transit to sell traffic (or for that matter, Google uses search to sell traffic).
Absent of a clear business model, humanity in itself can’t sustain itself over the long run. The “inbetweeness” Eslite preach would be something that’s more sustainable.
PS: I first visited Eslite in Taiwan around 2015 and was beyond impressed, especially that was the time when American bookstore was consistently struggling (and still somewhat struggles to this day, especially independent bookstores whereas Barnes and Nobles is having a second spring). I later visited Eslite in their Nihonbashi location when they first opened their first Japanese store and was beyond amazed - the store served as a cultural ambassador for the Japanese to learn more about the Taiwanese culture (and I could have been mistaken, but I think I saw this book in their Nihonbashi store, and thought one day I will read it).