When a creature is affected by the Goad mechanic, it will be forced to attack in its next combat phase, and it must attack a player other than the one that applied the Goad, if its able
Giving two Map tokens is a worry, so much so that it might be worth pointing this at your own creature to fizzle, say, an adventure removal spell in an artifactfall deck
You potentially can also use the front side of Invasion of Shandalar to return massive finishers like Portal to Phyrexia or Atraxa to your hand, flip Invasion of Shandalar, and drop them into play on future turns, which sounds powerful if you can find the time to get it set up
Put simply, if you discard a card with madness, you then get to exile and then cast it, typically for a slight discount or with an upside to using that method
Please don't hit mana rocks that people need to cast their stuff like Arcane Signet