Pros
Bank of lessons and questions allow you to meet the needs of 80% of students without additional preparation.
Cons
Lessons are not long enough to cover a 50 minute session, yet some students will not be ready to move to the next lesson. So an elementary school lesson of 7 slides will need to be heavily supplemented. Students who require more visuals or who have special needs take additional preparation. No prep time is paid. No training time, even in the required onboarding phase, is paid. The unpaid onboarding, in particular, is illegal.