This game is much closer to Trivial Pursuit than it is Assassin's Creed. The importance of accuracy depends on the type of game and when the point of the game is specifically testing the player's knowledge, a lack of accuracy is game-breaking.
I do want to lend support to the idea that he series tries to balance accuracy with its gameplay/narrative foci, though. IIUC, they get a lot of details that Hollywood movies and even documentaries get wrong (by virtue of digital production). Origins and Odyssey included modes that allowed player to move through the world as if it were a living museum, reading passages about people and places as they were encountered.
Overall, it's nice when artists dealing with historical subjects understand that they're presenting imperfect models of the past, and state so, so that viewers can consider what might be accurate and what might not be.