Answer:
The impact Mama's decision to give the quilts to Maggie has on the development of the plot of "Everyday Use" is the Dee wants to keep the quilts to appreciate for "her heritage" but Maggie wants to use it as its purpose. This led to Dee believing that Maggie can’t appreciate the quilts just as how she sees them, and she thought that the quilt will be put to “everyday use” by Maggie and within 5 years or so, the quilt will turn into a rag.