I think anything worth crowns should be worth gold. Even if it's for subscribers only. It would be fair to be able to buy crowns items for ten time as much in gold, like for school homes.
What do you think KI just does everything for free? Someone has to pay the Developer team to do what they do, that somebody is Subscribers and/or Crown buyers. A lot of people PAY a MONTHLY SUBSCRIPTION to KI to play the game, and others use Crowns. If there is no Crown Buyers there are the Subscription Buyers.