It's a Survival of the Fittest on legs, that taps to use its ability
In short, whether it is suitable for PSA is easier to judge if you think not just about whether it is an expensive card, but whether it is a genre that is easily compared or where condition differences are reflected in the price
Mew ex, for example, has a powerful attack that allows it to copy a move from the opponent's Active Pokmon, essentially making it the perfect counter to just about any deck
A security guard mentioned that he hadnt even heard of trading card games in years, having last played Pokmon and Yu-Gi-Oh
It takes a lot for me to get excited about another +1/+1 counters card, and Warden of the Grove wouldnt quite do it for me if it was just another riff on Master Biomancer
I'm the lead of the Future Future League (our internal Standard playtesting), and I make the final balance calls for our Standard-legal sets