In the 1001 Nights, a King is so upset over his wife’s infidelity that he orders her killed. He then requests a wife every night (sometimes every 3 nights?!) and then, because all women are untrustworthy, he has them killed at dawn every morning. Along comes Queen Scheherazade. She tells the King stories every night, and ends with a cliff-hanger every morning so he delays the mortal decree another day. This continues for years until the King finally trusts his Queen.
I’m not saying that audiences will behead you if you don’t supply a cliff-hanger, just that an audience member’s committment to a cross-media work involves trust, and cliff-hangers!