When a card's attribute matches the song attribute, the card gains a 20% (+ additional matching bonus from the Bond Board) boost to their Stamina and Technique stats. The boost does not apply straight to their Appeal stat, instead, it applies as a bonus to the Voltage gain from taps. (Whether the bonus is applied or not depends on the specific Skill. This is why the attribute bonus does not apply to the Appeal part in the SP Power formula, but does apply to Vo+ Skills.)

Note that the SBL 20% boost is not the same as the Attribute Match boost - that one actually applies the boost to the Appeal stat.

When an accessory's attribute matches a card's attribute, that card alone gains an extra 10% for the accessory's stats. The other cards in the strategy are not affected if they have a different attribute. Additionally, there is no bonus for matching the song attribute.