During any turn you use this effect, you cannot conduct your Battle Phase
With lots of hard-hitting vanilla characters and the Edward/Newgate character card, it meant that getting to the late game and surviving one extra round to deal out big attacks felt very good
Why can red kill planeswalkers out of combat when no one else can
The safeguard ability nullifies damage from ex Pokmon, which can potentially trap you into an unwinnable state if you arent careful
Three is a perfectly round number in the beginning of the Pokmon TCG, in STSs (Super Trainer Showdown a Worlds like tournament, which was held in the Wizards era of the Pokmon TCG) there were decks that ran 3 of EACH card in their deck
What's more, MTG Arena decks are three times the size of Pokmon Pocket decks, and you need to have four copies of your best cards instead of two