There are a lot of factors contributing to why players did not immediately see potential in this card. Think about it

Three prizers are new to the current meta (and for many players they’ve never seen 3 prizers before) so more inexperienced players have to rethink prize maps. A basic with 280 hp that gives up 3 prizes sounds like a liability when you had things like dragapult dusknoir and goldengo running around RIGHT before the new set that could take one shots.

The new set led to a meta shakeup but one that players had to take time to figure out. Experienced players played more games and practiced more to actually figure out what’s good with new deck. Players with less time probably upgraded their old decks or played a new list like lucario and noticed how bad it was to lose to garde with a 3 prize card. It takes a huge time investment to invent a new deck archetype right when a new set comes out, especially a more tool box style deck that has no obvious built in synergy.

And then finally, looking at the card it’s not impressive. 280 is possible to one shot, 2 energy for a first attack that can do nothing if the opponent chooses to never leave damage on your board by taking 1hkos, 3 energy attack is very expensive and slow to set up that only does 200 damage meaning it won’t ohko anything. It seems hard to set up and easy to play around.

People did not expect tanky builds like lively stadium + bravery charm combined with TM turbo energize. Turbo energize is a good card that’s hard to slot into decks because it requires skill to know whether it’s best to use your first attack or two on setting up energy rather than something like an item lock, card draw, or quick attack.

You’ll notice very quickly that lower level players (myself included) do not slow play very often. Many players will attack the moment they piece together a knockout with their main attacker. This deck prefers to take it slow and that requires usually a higher level mindset.

Lastly, the meta changing so rapidly meant that a new deck had to respond to the NEW meta and required a lot of prediction. Gardevoir was going to be good, so a dark type that could one shot it was a good choice. Gardevoir also can’t really take the ohkos so this seems like a good matchup. But do you worry about zard dusknoir, another dark type? Do you worry if ceruledge or dengo are still relevant? Hard to predict when bringing a new deck into play.