Sieges are owned and controlled by the same player, i.e., the player that casts the card
If Jim gets banished in the challenge you still get to play a Location for free, and if that Location was The Library, you'll also get to draw a card
After a week of farming daily quests, buying packs I finally unlocked the last quest that would be able to unlock the final few decks
All that said, I don't think you should ignore these cards outright, at least not all of them
It wasnt until the rules update with Modern Horizons 2 that this was erratad on the older cards
He also not only has double-strike, but if you land a hit on an opponent, you can put a goblin from your hand into the battlefield for free