In the early game it initially denies you some information on your own state as well as lowering your potential option power (as in, it might not actually lower your option density but any options it does bring will be less potent than actual cards you could play)
If exile wasn't needed, she can buff up a blocker with +1/+1 and first strike, or, if you're really desperate, make a Samurai token too
I attack them down to 11, Griselbrands lifelink puts me back to 11
You want the king of the dragons
The best target, however, will almost always be Merlin, Goat, who truly seems to be the G.O.A.T
The most common pairing is Numa, Joraga Chieftain, but I prefer Thrasios, Triton Hero (one of Magic's best merfolks) or Tana, the Bloodsower for a better color identity