Why is the armature of an electric bell made of soft iron?

In an electromagnet the core is the space filled by a soft iron and then we have a soft iron core.

We use soft iron for electromagnet because we wish to make electromagnets temporary magnets i.e. they should be magnetized as long as current passes through the solenoid wound around them and become demagnetized when no current is passed.

Soft iron has low retentivity thus they lose magnetism when current stops flowing.

But if steel or other iron is used then it will become permanent magnet, i.e. it will still remain magnetic even if the current through the solenoid is switched off.
Due to his reason the armature of electric bell is made of soft iron.

Regards