I think it is an important element in the novel.Because at first Heathcliff were poor,even Catherine wanted him to be richer and gave her the noble life.But Heathcliff had no money so the emotion between he and Catherine was objected by everyone.So money depends a lot.
Later,Heathcliff became rich and he got the Wuthering Heights and the position.He used his money to revenge.He became the master of many thing then.
So money was important to the characters in novel.It caused the social conflicts.
主观观点,完全是我自己认为的,没什么书面支持,