What is an advantage to using electromagnets rather than a regular magnet?

An electromagnet is a kind of magnet whose magnetic field is created by flow of electric current. The magnetic field disappears when the current stops. The greatest advantage of an electromagnet over a permanent magnet is that it has the advantage of controlled holding power and on - command release. Through the application of controlled DC electric current, electromagnets have the ability to attract and hold ferrous materials with varying degrees of force and to release the item as required.

That is false even though water expands when frozen nothing changes at all