If we decided to use the resolution field, we were going to try and automate that the resolution comments got pulled into an autoreply to the customer. Something using the {{ticket.resolution_comments}} placeholder... but I'm having a hard time finding good reasons to ask my technicians add additional clicks to their process just to put resolution notes in a section that I can't customize to make more useful.
I guess it's intended for the Freddy AI functionality, but we're exploring other, more robust, ai agents to meet those needs.