Eh, tbh I'm torn on the issue. I encountered games you have to beat 4+ times to see the true ending. Games where you need dozens if not hundreds of hours of mindless grinding to beat some hardcore boss. Games where progress is slowed down artificially making you go by inch after inch only about once a week to make sure you don't get to the end too fast.
Am I opposed to loot boxes? I am, never bought one. Am I opposed to adding shortcuts to get to the end of these grinds faster? Maybe. I wouldn't buy into them, but to me a long grind is already shitty enough to begin with, yet a lot of Internet favourites are insanely grindy and a lot of people would have probably loved to have spent 5-10 bucks to get to the end faster. I am not invested in games enough to spend money on such things or grind dozens of hours just to see an extra cutscene, but honestly this ending doesn't sound any worse to me than, say, Destiny 1 asking for hundreds of dollars for the full package, on-disc DLCs, loot boxes containing OP weapons and such. WB is trying a weird concept here, and I'd never buy into it, but it's far from the most disgusting practice I've ever seen tbh. Fortnite, as a recent example, is 10 times worse when it comes to progress.