This is pretty much the only time you should do this on your turn since ideally you would already have a Wurm or two in hand and can do this at the end of your opponents turn so you can attack right away without them knowing what is coming
Provided you can generate a bunch of mana (or infinite mana), you can exile your library
This means that Kida, Royal Warrior can provide some much needed defence early on to protect those cheap and weak characters with useful abilities: such as steels own Razoul, Palace Guard - which has plus two willpower when undamaged - or emeralds Morph, Space Goo or sapphires Scrooge McDuck, Uncle Moneybags
(Whenever this creature blocks or becomes blocked, it gets +X/+X until end of turn.) Creatures your opponents control attack each combat if able
Most life-gain cards seem to be three or lower in cost, and most life-gain decks can easily gain three life a turn
Sygg, Wanderwine Wisdom // Sygg, Wanderbrine Shield Merfolk fans, I see you