Both sides of this just have unlock triggers; the card doesn't do anything as it sits on the battlefield. There's no reason for this to be an enchantment except that they were trying to shoehorn some stuff into the set's marquee mechanic.
Same with Meat Locker // Drowned Diner and maybe some others that I missed. If they couldn't come up with enough actual-enchantment effects, that might be a sign that there wasn't enough design space and they should have abandoned this mechanic or narrowed its scope. Like, maybe they could just have printed a few Rooms at rare/mythic and skipped the meta-mechanics that care about when you unlock rooms or how many unlocked rooms you have.