Correct. Do you want to have an incredibly powerful party that can 1 hit any boss? Then play the way of the card modder. No doubt you know that enemies level up as you do (they scale to your level) so levelling up in ff8 is actually detrimental to your overall parties power over enemies. This is why bosses do not give EXP after battles, but lots of AP. By card modding enemies you will be able to finish the battle without gaining EXP but still gain AP, which is required to learn abilities, of course. You will want to learn for all other GF's their refine skills as this will be the means to create magic from items you mod from cards. I would say give priority to this and then learn the stat-J's. Strength, Hp, Vit, Spirit, Mag (not that necassary). And dont forget to check bosses with the 'draw' command to see if they have a GF, just a help tip for you whilst playing the game.
If you have anymore questions, post here ill be glad to help you out.
Bookmarks