Blades have zigzag edge can be used for decoration or to prevent fraying?

There are scissors used in sewing called Pinking Shears that are used to cut out seams, and yes they prevent fraying. These scissors are to be used for fabric only.

To use otherwise would dull the scissors edge.

There are also craft scissors with a zig zag patterned edge used to make decorative edges for use on paper only. These scissors do not work on fabric.