This is good because of the Twinspell, otherwise, this would not be worth putting into your deck. Also in pure Paladin decks, you can get this randomly generated which means flooding the board with no deck slots wasted.
If you think this is bad, then what about this....
Turn 1, Brazen Zealot. Turn 2, Air Raid. Brazen attacks for 4 damage. If they cannot kill the Brazen the opponent is in deep trouble. Ping classes can go ahead and kill it, but other than Mage, will be tanking another 4 damage.
Then you have Sky Claw OR Air Raid again on turn 3. If that is your curve, your opponent will not have a chance.
This also can work in a Highlander style deck, giving you 2 spells for 1 card slot AND board presence.
How is this bad exactly?
It's not. People (inexperienced people at least) always underestimate the power of low mana cards like this one. This is the kind of card that can get you off to a start your opponent will never recover from.