So this is an example of Jane Austen's irony that those of us who are not as well studied in the Regency Era don't catch. Mrs. Elton in this scene imagines that she is being extravagant and a glamorous hostess. She is actually being cheap by throwing a card party instead of a dinner. Oh thank you so much for pointing this out. It is always good to have more reasons to ridicule Mrs. Elton.