The add-on is super easy to use and EXTREMELY valuable for students and trainers. To determine the value of the add-on for my junior high school students, I wrote a short narrative with clear paragraph endings. With two clicks (open the add-on and click "Create Google Slides), I had a slides presentation of my story. Students could write a book in Docs and then illustrate in Slides!
Even better than that is the "Create Speaker Notes" options. How often have your students read their presentation with the back to the class? I want to hear students share their knowledge, not read their words directly from the screen! This add-on reinforces that the slides support student words. I can see this really helping speech and debate students, as well as adults.
As for the Roster to Slides option, well, that is my favorite code. Write a list of student names, click Roster to Slides, and a slide deck is created with everyone's names.