In normal life, we wear masks. In a repack, masks suffocate. You cannot maintain a persona when you have dysentery, when you wake from nightmares, when you run out of tampons, or when you sob for a lost family member. The trope weaponizes vulnerability.

Fake dating to make an ex jealous, a marriage of convenience for financial or political gain, or going deep undercover where they must act like a deeply in-love couple.

"Always."

Some storylines have become iconic, thanks to their well-executed forced repack relationships:

Solo careers are risky. A forced repack relationship creates a "unit brand" (e.g., a fictional couple in a drama or a "best friend" duo in a group) that can sell variety show appearances, CFs, and fan meetings long after the original content has ended.