I don't have any experience with actually testing the PR-Manager out indifferent situations but he has a slight merchandise and attendance boost (gets more fans in the door and makes them more likely to buy slightly more expensive tickets). I believe this is regardless of any promotion/demotion bonus/penalty.
Personally I think it is important to get a Crowd Involvement or National Appeal specialty for your PR guy because that actually helps your team in game and can help lead to wins, which really matters and what influences the fan survey the most.
Murray/Harris/MPJ/Grant/Jokic - 2020 NBA Champs