In reply to ByEek:
heel and heal are different words.
look up healing by primary intent or secondary intent.
If the wound edges will oppose naturally then yes it may leave less of a scar than to place sutures, but if the wounds gapes due to the way the tissues are tensioned / movement then it may leave a much bigger scar / indentation to leave it to heal naturally.
Other times in the case of a graft then sutures (or staples) may be needed to hold it in place whilst it revascularises.
Skin glue is often used for minor lacerations to avoid the scars left by the sutures themselves but is only appropriate when there is little or no tension accross the wound.