The main advantage of temporary magnet is that we can change the magnetic flux. Magnet have two Regions called Magnetic Poles with the Magnetism both in and around a Magnetic Circuit generate an indivisible line of flux around it. These line of flux are Referred to as the "magnetic field" of the Magnet. Soft magnets are temporary they only produce Magnetic field while an external magnetic field is present and lose nearly all their magnetism once the external field is removed. Hence the Magnetic flux can be changed in temporary Magnets.