I was a bit surprised that Singapore hadn’t had book vending machines before now.

I mean there have been book vending machines in Australia for quite a few years now. The hotel in Sydney (that I last stayed in nine years ago) had a book vending machine back then (and for several years before that) – my main issue with it was that the range of books was a bit vanilla (ie – not enough crime fiction!) but it did have adult fiction, junior fiction, picture books and business non fiction. It was basically a (very) mini airport bookstore in a machine.