If you do this, Emrakuls madness ability will trigger, and this trigger goes onto the stack
Ross mentions Mono-White Hammer (Lurrus) as a primary reason to want Turn 1 and Turn 2 interaction, but my experience is that the cheap interaction is all trash that buys fractional turns and eventually loses the fight to Urzas Saga
River Bear River Bear has a reasonable enough mana cost that it can be played earlier in the game, especially in a green deck
The only obligation you really have to the online universe here is to finish the current match youre in
Its also worth noting that Walking Ballista might tick up a bit in response, though the card is so close to rotation that it could just keep slowly dropping even if it starts to see more competitive play again
On the one hand, I wouldnt recommend playing Kaza in most competitive settings because its not exactly a powerhouse card