"suggests that readers really altered their preferences to avoid being seen with a physical romance novel" I don't think that is necessarily what is happening,

"suggests that readers really altered their preferences to avoid being seen with a physical romance novel" I don't think that is necessarily what is happening, at least not primarily. People who read romance novels tend to read a lot of them, so I think that simply reducing the friction of purchase and allowing you to buy it and then immediately read it has more to do with the appeal.