Try sewing a sample to see if it will work for you. I have made a bed quilt using slippery satin (and spray starch) with good results, and personally I don't see any reason for not using taffeta. Many years ago vintage type quilts used all kinds of fabrics, including taffetas and silks especially in crazy quilts. I wouldn't want to have to wash it much, so probably only have on display is best, and out of direct sunlight.