I may be wrong, but I think it could also be used to suggest that that writing style is so dense, complicated, or unusual that getting into the "rhythm" of reading it is difficult, if that makes sense.
I tend to agree with bibliolept on this. "War and Peace was difficult for me to get into" suggests that I didn't get interested in it because it was just too complicated, dense, etc.
I'd guess that this nuance is because of the presence of the word difficult, which, on its own can refer to a film or book being too dense, complicated, etc. If we use "to get into" without "difficult," it doesn't necessarily have this nuance. "I just didn't get into War and Peace" might mean I wasn't interested in it for any number of reasons.