When you look into blue, you find a lot of great cards, that return lands to your hand, most of which are generally useful to some degree
Instead, it helps you to grow your attacking creatures with counters whenever it deals combat damage
If everything goes right, and Jace resolves, he will enter the battlefield with 6 starting loyalty, due to Doubling Seasons effect
Brudiclad creates a Myr token at the beginning of combat on our turn, and also gives our creature tokens haste
Jin-Gitaxias is spiking because it pairs really well with one of the FF Commander precon decks, Scions & Spellcraft
I have even created a coffee table book about them and a company called GAMENOOK that makes accessories for them