Craft Essen card effectiveness

Buffs to card effectiveness increase all aspects of the card that are a part of it's base effect. So yes, arts cards will give more NP along with damage, quick cards will give a better chance for critical stars, and buster cards will do more damage. Also, if I remember correctly, it will improve the critical star drop chance for arts and buster cards, and the np gain for quick cards, as each has some small amount they provide from the start. However, this only applies for basic stats of the card, so buster cards will not gain any np, nor will their gain be improved by the buff when coming after an arts card first bonus.

Any card type bonus increases all effects that card type produces, including NP gain, star creation, and damage. This is true of craft essences and abilities. Also important, the damage from card type ups increase damage multiplicatively with damage boosts, Ie. 50% damage + 50% card effect = 2.25 times damage, not just 2.

All aspect of the card:
Buster up increases damage and stargen of buster cards (who is very low, so not many difference in this, unless it has multiple hitcounts in a massive buster up).

Arts up increase NP gain and damage of arts cards.

Quick up increases stargen, np gain AND damage of quick cards.

Also different buffs stack multiplicatively. If you, for example, Tengu Strategy+quick/arts up someone, and them uses that card, the NP gain from the involved cards will be much higher than with just 2 Arts Up buffs. Same for stargen up on Quick/Buster cards+their card buffs.