I can possibly see the need for up to three full keyrings worth of keys.
In any case, this idea should def. not be a priority - if locks get added, then the ability to specifically target doors for destruction comes in and the soak on doors drops to a quarter of that compared to the soak on a house and then nobody destroys houses to get at the goodies inside anymore, they just bust down the front door.
Sounds okay, but I'd want belt-based keyrings, wider city gates for wagons, rotatable buildings, and tons of other QoL changes first.
Build a palisade to protect your belongings and then spend 90% of your time behind it. Building the gate gets you a key. Also, enjoy trading for metal if you ever need another copy.