After lowering the amount of cards in hand by 1, both players now have to trade a card in their hand if they want to add a new one
This difference isnt just about individual cards
Holo Pokmon cards were likely made to boost the rarity and value of certain cards
Agent's Toolkit is such a sweet card, entering with an assortment of keyword counters and handing them out as you please
While many of those cards were either cut or changed dramatically, we still ultimately felt this limitation keeps the card squarely in the desired zone of usage and future-proofs it should we push fast advance tools further in the future
For example, if a creature has three +1/+1 counters on it and two -1/-1 counters are put on it, state-based actions will remove two of each of those kinds of counters, leaving the creature with just one +1/+1 counter