It can, and for many people that’s one of the things that draws them to the idea of burial quilts. Not using a casket allows for the borrowed elements that make up our bodies to return to the earth. Inside of a casket (which is often placed inside of a concrete vault that is sealed water-tight) the organic material in our bodies can take hundreds of years to return to the earth to support future life. Natural burial cuts that time down to weeks in the case of soft tissues, and less than a decade in harder tissues.
Some people choose to have more of a hybrid funeral: they want a burial quilt for the softness, color, and sense of homeyness that it offers but still prefer to have a casket. In this case, the body is still wrapped (see these instructions here for more information) though the quilt itself may be made out of a thinner material since room in the casket is limited.
