When you planeswalk away from Mount Keralia, it deals damage equal to the number of pressure counters on it to each creature and each planeswalker
The casting cost, the flavor text, the mechanics they all riff off of Nivs endless Curiosity (which to be clear synergizes incredibly with the first two versions of Niv, and is a straight up combo with Niv-Mizzet, Parun)
This card is great for a modified-centric deck, as Thundering Raiju deals X damage to each opponent when it attacks - with X being equal to the number of modified creatures the player controls that aren't Thundering Raiju
For an extreme example, compare Ali from Cairo to Fortune Thief
Jin-Gitaxias, Core Augur has flash and gives Jodah's player a massive advantage in cards, and Sheoldred can force sacrifice while reanimating friendly creatures
The Payoffs But whats the point of all of this work