The speaker at our guild last night discussed this. She pinks because she hand sews everything using English paper piecing. So the paper ensures the piecing is accurate. She discouraged it for machine piecing because it makes it hard to get an accurate 1/4 in. seam.
She pinks because her pieces are often carried around for a long time before they are quilted so it helps with the raveling. She also hand quilts all her quilts so they "live a long time as tops".