You are probably giving some cards away by playing this
Last but not least, the design of a card can also influence its popularity
If there's no exiled card when Unidentified Hovership's third ability resolves (most likely because its second ability hasn't resolved yet), the ability won't do anything
I have a more detailed explanation of these in the introduction of my Graveyard Overdrive blog
It means you can get Excalibur, Sword of Eden down quicker, and it means you can turn a Loran of the Third Path or Boromir, Warden of the Tower into a cheeky one mana play while deploying something bigger and scarier
The modes are quite different from each other, too, but giving your whole team hexproof, while maybe slightly over the top as most spells only target a single creature, is a good bit better than just giving hexproof to one of them