If this card somehow enters the battlefield with its back face up, it didn't transform, so you won't choose an opponent
While proliferating multiple times, players can't respond between proliferating the first time and proliferating the second time, and so on
A canny Steelsong player can be singing by turn 3, wiping their opponents' slate clean while racking up lore at an obscene pace via Sleepy's Flute
By releasing starter decks as each new set comes out, even longtime players are introduced to new strategies that they may not have thought of previously
Market prices change over time as copies are bought and sold
Whether it's protecting your creatures, cheating finality counters, or just smashing with big green creatures (my favourite thing to do), these are definitely good excuses to splash out on a precon or two