The idea of this, which isnt clear from the Illumineers Quest: Deep Trouble rules, is that you get a reward when you defeat Ursula for the first time
They are: Rissa Blades Lee - if you cast an instant or sorcery this turn while you had two or more instant or sorcery cards in your graveyard, collect Sleepy Sovka - if you cast no spells this turn, collect Miron Tillas Jr
Bloomburrow is the 101st set for the long-standing TCG, and will contain 281 regular cards alongside further variants, Commander-only cards, and other options typically available in Collector Boosters
however, it is not the best-positioned card in the format
The good news is that it comes with 8 booster packs and is the same MSRP as 8 booster packs, so from that perspective its not bad value