Gate-Driving Transformer Role

Often I've seen 1:1 or 1:2 transformer used in examples for gate drivers like the LM5112. Some of these transformers aren't even connected to the gate per se and there's no indication of whether they're used for anything other than decoupling. Can anyone just give a breif rundown of what purpose the gate driver transformer serves and whether it's beneficial (or necessary) with the LM5112.

Isolation is the word your looking for.

Also, it a way to drive high side MOSFET's without bootstrap circuits.