Using a mask by stickers will allow you to add additional graphic effects to your stickers, and diversify the possibility of their application.
The peculiarity of this type of mask is that it interprets the sticker image as a mask. This means that you can get a mask adapted to the size, position, rotation and transparency of the original sticker.
Among the options for use: cutting out shapes of a given shape on a specific part of the human face, body or animal face, as well as positioning other layers and custom photos in a given place, cropped to the shape of the posted sticker.
The photo below shows that the hole on the cheek with blurred borders takes into account the location of the face, its size and head rotation.