My theory about that is that unused cards are going to be worth more than cards with experience because the ones that are battled are going to be more common than the unbattled ones, because why would you use a 400-800sbd card, right? And if I'm wrong on that and that experience gives value, then you can just battle them to get experience, so I'm going to play it safe and not battle mine until time tells
You can never take experience away but you can always put it on, ya know?
You will be able to gain XP from battling but that takes so long so I maxed out mine. I can't wait to battle! I love this excitement! #teamsteemmonsters