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.
There are benefits to them being enchantments. They are permanents, so can bounce it back to hand and replay. They can also be flickered and there are creatures that can relock/reunlock the rooms. Being an enchantment instead of something new allows you to interact with them with spells like disenchant and you can splash them into enchantment decks instead of them being stuck to one Room deck forever.
