The PM will only observe and not allowed to for any kind of distractions and don't forget there is a Flight Instructor onboard also, secondly If you look to the evaluation method its not that kind like completion standard with +-100 ft for example its using a positive method of evaluation and at the end of the flight the PF & PM will switch their positions & vice versa as we see here this method will enhance the communication between the students in flight tasks and will build this habit inside them from the beginning to work as a team. One of the suggestions here the PM will read the checklist as requested by the PF for each phase of the flight.