As with most adventures, it's not the best rate in the game for the effect, but it's not bad, either
It only takes a couple of these skeleton tokens to overwhelm your opponents considering they have menace and usually eat whatever blocks them
They work against mill in a similar fashion: Shuffling your library back into your deck against a mill deck is equivalent to resetting your life total to 20, 40, or whatever against a more standard Magic deck attacking your life total
You can also put counters on an active Nexus via Steel Overseer
Speaking of artwork, the pictures on the Lorcana cards are gorgeous
Further down in this article, you can read about both The Lord of the Rings: Tales of Middle-earth Jumpstart Volume 2 and the new Scene Box cards and products