That's because persist checks the creature as it last existed on the battlefield, and it still had -1/-1 counters on it at that point
It makes all of your Planeswalkers capable of using their ultimate the turn you play them, and if you combine it with cards like Doubling Season and Hardened Scales, you can almost instantly turn a 1/1 into a 10/10 with no issue
note though that if you do that you need to target it while the ETB effect of Worldgorger is on the stack if using something like Crystal Shard to do that, but if you do, that's another infinite combo most likely
Lets take a look at the Ursulas Return card list, to check out which Disney Lorcana cards were hoping to bag next
To play this game, each player has a deck comprised of 60 cards, which includes spells and creatures which combined are used to defeat the opponent