They just prevent damage, which, like gaining life, is rarely worth spending a card on
When you get to play a bunch of instants, you can cast spells on your opponents turns
(Side note: announcing that you threw a planeswalker into one of these boxes may have the side effect of new players ravenously buying out every single box in hopes of being the winner of the Golden Ticket)
You can even sort and search your collection with the familiar parameters offered in deckbuilding
Uncommon artifacts in OTJ LImited The two stand out uncommon artifacts seem to be the vehicles
Now a fury-filled planeswalker, Ajani can pump up your Cat creatures with +1/+1 counters, create more Cat tokens while dealing damage, and wiping the board to make all your opponents have to rebuild from practically nothing