What is the significance of the scene featuring the display and discussion of the pair of screens painted by Elinor?

This scene is significant because everyone complimented the screens including Mrs. Ferrars. Ironically, as soon as Mrs. Ferrars was told Miss. Dashwood was the artist, they were waved off as pretty.

The Colonel, though disclaiming all pretensions to connoisseurship, warmly admired the screens, as he would have done anything painted by Miss Dashwood; and the curiosity of the others being of course excited, they were handed round for general inspection. Mrs. Ferrars, not aware of their being Elinor’s work, particularly requested to look at them; and after they had received the gratifying testimony of Lady Middleton’s approbation, Fanny presented them to her mother, considerately informing her at the same time, that they were done by Miss Dashwood.

“Hum” — said Mrs. Ferrars — “very pretty,” — and without regarding them at all, returned them to her daughter.