What do the wooden benches, hand-carved butter churn, dasher, and quilts represent for Dee when she returns home to visit?

The thematic importance of the items you mentioned is connected with the title of the story. Dee cannot understand that Maggie and Mama want the quilts for everyday use. Dee sees the quilts, butter churn....as representations of a dying culture. Dee wants to appropriate her own heritage to display a culture that she feels is dead and antiquated. Dee refuses factory made quilts because she cannot exploit them. Both Dee and Mama see the quilts as a functional representation of their story and heritage.

"Dee (Wangero) looked at me with hatred. “You just will not understand. The point is these quilts, these quilts.”