Here's what I've read from Mabidata.
Zero Cards:You can rebirth your character into a Hero with the skills of said Hero.
Hero/Elite Cards: You can't use either to rebirth a character, but you can use it to create new character. To use both you must have a character with a cumulative level higher than the card you are going to use.
Hero Cards give new character 400 AP / 1000 Cumulative Level to start out. (Require level 1000 char), 14900 Points
Elite Cards give new character 800 AP / 1200 Cumulative Level to start out. (Require level 2000 char), 19900 Points
Both cards also have AP support System like Zero Card System
Both cards also comes with preset skills similar to Memorial Cards
Both cards give a Hero Talent Emblem, Druid Emblem for choosing Merlin, and Soul Star Emblem for choosing Diva. When equipping the Emblem, you will receive the respective talent bonus of that Hero Talent even if you didn't have the Hero Talent. However, if it is same talent it will not stack when you have a talent relate to the Hero Talent.
And the outfits for the Hero's are also in the cash shop I guess who those who don't want to get any of the cards and just care for the outfits.