The constant stream of free spells off the top of your deck is just too much value for your opponent to deal with, and the ability to hit your opponent for 10 life with Kefka's Tower shouldnt be underestimated either
But the market price for foils is $5.87
Do the first for someone mana screwed to help them out (there is always someone) and then the last two to folks breaking an artifact like Skullclamp or Mind's Eye and then punish the other for holding a full grip
Galadriel, Light of Valinor is limited to three triggers per turn, but if you can trigger one or two reliably, its already very good
There are plenty of other kinds of decks you can build and I cant list all of them, but these archetypes should be enough for you to understand what you can expect from other players and point you in the right direction to get started
Ramp it to the battlefield, and it's even untapped ready to be used