Hmmm, interesting to hear your experience from that: the cards did not appeal to me in abstract.
I'll be honest, I also wasn't initially interested in cards. A value add, for sure, but I wasn't thinking they'd be that useful.
But there's more benefits than I had thought.
First, as I mentioned, passing cards around made character gen and leveling way easier. Sure, an app can do the same thing, I wouldn't dare touch Pathfinder2 without app support. But we've been playing old school without digital aids or just a tablet for the DM (I only use it for combat). But I also got the distinct impression that the players all really preferred having the cards to read and weight their choices. We just hit level 3, but I also showed them their level 4 cards, because they're starting to think about builds and whether to take an level up slot to get an additional domain card.
Second, because all the material has to fit on a card, it encourages brevity in design. Can't put all the text for Wish on a card. Domain powers are concise and evocatively designed because they have limited space. That old saw about restrictions breeding creativity ... well the dimensions of a card are certainly a restriction.
Third, sure, I like the aesthetics of cards, I play MTG, but having an art piece with each element of the game does have value. I lauded the 2024 new Core books for the increase in art. Every ancestry, community and domain card has unique art (subclasses share art), and that meant a lot of art, while still keeping the core book (singular!) less of a textbook size.
I'll be honest, I wasn't going to buy the book, but I found out about a pre-order sale. All the game content is free *(yes, only one of the six campaign frames, but all the core player material and adversaries/environments for the GM are there), the full SRD is out there. And I do think the cards are enough of a value add without the other stuff in the Daggerheart book to have made this a great purchase.