Because phasing occurs at the beginning of the untap stage, several savvy players developed decks that combined the two, allowing cards to be phased out "permanently." 43
That means it might not net you that much mana and you might not have much to spend it on when it does, and, as mentioned, two mana is an enormous amount to hold up
Still, once it resolves, you can choose how to kill your opponent slowly by either casting spells from the top of their library without paying mana, shrinking their hand, killing their creatures, and, if they've survived long enough, exiling all their non-land permanents with the ultimate
The game will prompt you as though you were able to cast a spell or activate an ability, even if you are not, concealing your situation from your opponent
The other issue with planeswalkers is the way they run away with a game when theyre not answered, as they put your opponent further behind every turn you activate them
For an in-depth retrospective and analysis into McKinnons MTG art style, check out this video: Thalia, Guardian of Thraben by Steve Argyle Thalia, Guardian of Thraben has been redrawn so many times, partly because its been reprinted recently in the Secret Lair drops