I certainly would not call this as a digital exclusive feature as I can totally see same feature be easily implemented in physical realms, but still being able to play almost a mini game within a game is awesome. Let’s take a look at couple cards from HEX today.
What do these card have in common? Well it’s a guessing game. The interesting part of these cards are that it’s essentially are mind game. You and your opponent are trying to read other players mind. It is true that TCG itself has that element but these two cards forces that to even players who just play mindlessly.
Personally, I believe these type of cards are different from random effect. It’s not a luck based, but rather strategic.
As far as how good these cards are? Well, it’s only as good as your psychic power. The only downside for these types of card is that you will lose reading other players facial expression, tension etc. as the game is digital and you cannot really see how much sweat your opponent is producing from the sweat glands.