I want to break down this question and figure out once and for all which is better for playing and what is better for your wallet
Adding a creature that's effectively a 2/1 haste for 2 mana and a goblin is okay, and giving +1/+0 to other creatures you control can lead to a very powerful attack
Market Price $0.45 $0.03 Median $0.40 Prices from TCGplayer, updated 13 hours ago
So, one Reddit user decided that if Wizards aren't going to, they will instead
Flash blink spells like [card]Cloudshift[/card], [card]Ephemerate[/card], and [card]Essence Flux[/card] let you repeatedly exile threats or spells through Aang while also dodging removal and stacking ETB value
Adding Spellbook Spell Cards to the hand at the End Phase (up to the number of Spells activated after Spellbook of Judgment is resolved) is nice, especially in tandem with the Special Summon of a Spellcaster from the deck (of a level equal to the number of Spells)