Why is nineteenth century literature, and specifically Les Miserables, so notorious for its digressions?

Question

I have read a lot of literature from the 19th century and virtually all of it, no matter the nationality, is full of digressions as far as its prose is concerned. However, Hugo in Les Miserables seems to do it excessively. Not only do we get a fifty page account of the sunken road in the Battle of Waterloo, a rebellion in adjacent Spain that the French were interested in, a chapter detailing the house Jean Valjean and Cossette lived in when they were running away from the police, but now we need to know every aspect of the history of a specific convent in numerous chapters. What is the purpose of all of this? Hugo even tells the reader to pardon his digressions which is another digression.

Answer 1

it is all about using a new literary technique. the author tends to be omniscient and to reveal in the smallest detail the slice of reality he decided to present. it all began with Balzac. that is one of the reasons why critics call this type of writing: realism.
moreover these digressions can be seen as foreshadows of the stream of consciousness, used in The 20-th century by Proust, Woolf, etc.

Answer 2

Maybe digressions build momentum for the plot