Sometimes I'll use it to get an idea of what a person's writing style is like (90% of all 1x1 readings), or skimming roleplays if i'm looking for potential partners (rarely). I have been known to read one or two though... mostly because I happened to be in the 1x1 section at the time or the title caught my interest. There's no real logical reason why i'd read a thread over a book other then "I saw, I clicked, I left" and just... that thing with the internet where you lose time doing things unproductive. Although, a couple times i've been pleasantly surprised, or inspired, or impressed. I love reading RPs people have gotten into with lore, plots, pictures, and multiple NPC characters.

Oh and once or twice checking up on some ooooold roleplay buddies i've known for yonks - there's something comforting about checking in with a friend and seeing how their writing has developed, or if they're still into the same stories.