Welcome.

In Patch 2.4 we will have playable card game like in Final Fantasy 8, but producers dont tell us what will be rules of game and how we will obtain cards.

My suggestion is make it like on old games - they drop form monsters.
Explain: If you need Twintania Card you must drop it from Twintania on turn 5, but if you do it with full party drop rate is around 1~2% but if you do it from duty finder or help new player drop rate was increase to 10~20% - that will make old content playable once more and new players have another chance to pass Primals and Coils because more experience players will help them for that cards.

Please tell me what you think about tat system.