The legality of Magic cards that get their first printing in a Universes Beyond set depends on how they were released
I can see this being played quite a bit going forward
"There's no culture of accountability, just deep obliviousness while simultaneously maintaining the performance of awareness." Zaiem Beg (@zbeg) June 8, 2020 Wizards of the Coast noted in its statement on the card changes that it has more to do to make their games, communities, and company more inclusive
But theyre a part of the game
Unless the opponent has a way to flip it back up, which is highly unlikely outside of morph decks, the creature is essentially permanently a 2/2
(Put X +1/+1 counters on the creature that entered or create an X/X white Spirit creature token.) Whenever another nontoken creature you control enters, it endures X, where X is the number of counters on this creature