We checked the Kru Card: picking it up inside its hunting grounds (the Herb Town area maps) does raise Speed by 3 in the stat window (100 to 103 in our test). Two rules from the original game can make it look like it does nothing: a card's bonus only counts while you are inside that card's own hunting area (it pauses when you leave and comes back when you return), and Speed, Jump and item buffs do not add up - only the strongest one counts, so Haste, a speed potion, another card or a mount hides a +3 card. If you still see no change with nothing else active and while standing in the card's own area, please tell us the card and the map.