Throughout a lot of RPGs, the player comes across non dialogue sources of text, such as letters, notes, books, and other things like that you'll discover around.
Initially I wrote these out like regular text boxes, but I found that odd to read and it didn't 'flow' with the default text boxes like regular scene or NPC dialogue does. So I decided to do this instead;
This is sort of similar to what games like Dragon Age does with letters and notes, and I think it's much cleaner for the player to digest and read, especially since notes/letters/books are focused on just the text, and not the person speaking, a scene, or the environment. It allows the player to focus on just the words on the scene, similar to how the characters must also do the same with words on the piece of paper they're reading.