Its powerful but its a well-known, telegraphed line that invites removal and can sour a casual table, so read the room before you assemble it
The Punching Bag A Training Set boosts ATK, as well as shifting a Digimons Personality toward Heart and Affection - which are exactly what we need because the Zealous personality is located in those directions
The second best use is keeping Survivor allies that heal themselves alive when the encounter deck does one damage or one horror to allies
This can be found at the bottom of the card typically in one of the corners
In fact, the first deck protector sleeves (Top-loader) were quite rigid and designed only to protect collectible cards from wear
Here's a close-up of cards in this deck: Yes, these cards are extremely worn, but for its German productions NSV uses high-quality, linen-finish cards that can take a lot of wear, yet still riffle shuffle smoothly