Yes—an ordinary metal cookie tin can work if the film is protected properly. What matters most is keeping unexposed film dark, cold, dry, and away from chemicals.

Key points:

• Light protection is critical. Keep the film in a truly lightproof wrap or black bag; multiple layers such as foil can add protection.
• Metal helps as an extra barrier, including against some infrared leakage that certain plastics may not block well.
• Cold storage reduces fogging. A freezer or other cold storage is commonly recommended for longer-term storage.
• Keep it dry and away from chemical vapors.
• When handling unwrapped film, do it only in a genuinely lightproof room.

So the difference is not that a film tin is magically required, but that any container must help provide darkness, dryness, and clean storage. A cookie tin plus a properly lightproof inner wrap is generally fine.