Develop doesn't just trash a card and gain you two cards, one costing one extra and one costing one less, but it also topdecks the two cards.
A little perspective: I don't own Hinterlands IRL, but I do have the online cards and have played some 783 online games, not including playing through the Hinterlands campaign. Several of those games have obviously had Develop in them, and I buy it all the time, I like the card. Somehow though, I had no idea it topdecked the cards. And I've somehow never noticed "hey, why did I already draw my new Silver, I wasn't close to a reshuffle...". This has just blown my mind.
Anybody else have any stories of playing cards wrong for a long time, or not realizing the extra effects that some cards might have? Having never actually playing Develop IRL, I've never actually played it incorrectly, I just never realized the cards were appearing on top of my deck.