About that smirk...(spoilers)

[SpookRooster]

Here's a boring answer:

She's not evil because you can play Triple Triad with her. Evil characters can't be interacted with normally and you'd lose a shot at getting her rare cards if she betrayed you.

But there's a Nidhogg card...and Bahamut. Wait...you mean play the game with her. When can you do that?

[Aura_Shurifon]

The card argument isn't valid : She was dropping Tataru, Lightning and Urianger at the end of 2.55 and now she drops Tataru, Lightning and Firion.
And none of the cards are exclusive to her.

About the hide, she could have ask Edmond for a little help (Edmond isn't poor as far as I know)

As far as I read things, she seems to hide something but it may not be about betraying us. It could be a new (or old) friend that rather stay in the dark for now. Wait and see ^^

[MilesSaintboroguh]

But then why make an NPC be playable for cards and then, for example, kill them off? It'd be a waste.