Yes, paying life causes you to lose life
The web-slinging cost wasn't so restrictive that he couldn't cast spells, but it turned out to be a more interesting build around in practice
Kefka, Court Mage (Borderless - Surge Foil) - $114 Kefka, Court Mage (Borderless - Surge Foil) puts the clown front-and-center, while offering a transformation into Kefka, Ruler of Ruin on the other side - yours for just over $110
Blues entry on that list, surprisingly, targeted lands and could be used in concert with cards such as Rising Waters and Tangle Wire to completely ice out a foe from tapping a land for mana for multiple turns in a row
Fully excluding these sorts of effects can leave green completely anemic and uninteresting to draft, though