Paper books are a carbon sink though. The carbon that is held in that paper is held there for as long as the book exists for until it’s either burned or composted at which point that possibly decades old carbon gets released into the atmosphere.

Wood and wood products, if sustainably harvested and grown can be really good for the carbon budget because trees pull far more carbon in from the atmosphere while growing than they do once they’re fully grown. Meanwhile computers have a comparably short lifetime and require regular hardware replacements to continue operating which consumes far more materials and expends far more carbon than books, plus computers require energy to operate which also has a carbon cost, meanwhile books have a one-time carbon cost of their production and never again