The galvanic isolator is a good alternative to the isolation transformer. Not only is the insulator smaller and lighter, but it also costs less than the isolation transformer.
Advantages of the galvanic isolator over the isolation transformer are that the galvanic isolator has a limited weight, price and size. This makes it suitable for small boats where it does not take up much space.
A disadvantage of the galvanic isolator is that there must be a good shore-earth connection.