In case it’s not obvious to the TV audience at home, Ratiquette (and Rat-Speak) is a joke (that emerged from one of our players talking to rats during a game, “Squeak! Squeak, I say!”).
The best uses have come in unexpected moments. A character talking to rats when they have no one else to talk to. Bowing politely and asking a rat’s permission to share a meal. Asking directions from a rat, etc.
If you’re willing to bend credulity a bit, it’s quite a useful ability to be able to understand the intricacies of rat society. And if a game master is willing to insert a few rats here and there, the opportunities for good play can emerge naturally.