Dictionaries and Google Translate are good in different ways. Google Translate is particularly good on phrases.
"Dracula" was written in 1897, "Oliver Twist" in 1837. They are in difficult English. They are somewhat difficult for native speakers. They are much too hard for beginners.
In the 1800s novels were written in elegant English using long sentences, a large vocabulary, and complicated grammar. They are also full of cultural context. "Oliver Twist" was a protest again the Poor Laws. Since they don't exist today and we don't understand the history and the context, it doesn't have much impact now.
One reason why you hear about them is that they are out of copyright. They are classics, but they are not good for beginners.