The rewards for the main scenario roulette were boosted through the roof because of the cutscenes. They're rewarding you for putting up with it. As an unusually patient and tolerant person, I love the extra 50 tomestones per day I can get just by saying lame jokes in party chat.

However....these rewards apply to the roulette. Roulettes also tend to include players who didn't technically sign up for the roulette itself (first-time clears and/or manually selecting a duty to run).

At the minimum, I think unsynced runs should be immune to this cutscene stuff. You get no rewards from unsynced runs, and every party member has to join manually. Any new players in such a run would most likely already know what they're getting themselves into.