Features:

Fill in holes created when keying or rotoing out noisy blobs, scratches or other unwanted small objects.
Fill in small image regions along an image boundary that can become “invalid” after distorting or warping an image.
Fill in an area between two objects being lined up that don’t exactly fit together.
Fill in areas that have unwanted blown out areas, or other unwanted specks due to bad camera or lighting setup, or due to some unfortunate color correction that has been applied.
Fill in areas left behind after the removal of small tracking markers, crosses or orange balls.
Create nice color gradients and washes by filling in large holes.
Create interesting kaleidoscopic effects using a mirror fill on large holes.