People who study fun in games, gamification, and how to motivate people have written a lot about the concept of intrinsic vs. extrinsic rewards. The idea is that something which is inherently more fun is more motivating than having to do a boring activity for a reward later. Of course that is more of a theoretical concept, because whether an activity is fun in itself or not is not so easy to determine. I think that for most people the activities in their first MMORPG were inherently fun, but became less so with hundreds or thousands of hours of repetition, until the only motivation left was the extrinsic "epic" rewards at the end.

So it was somewhat interesting how Card Hunter worked nearly in reverse for me: Extrinsic rewards were more important at the start, and after a month their importance pretty much disappeared and I only play for the intrinsic rewards. The reason for that are the diminishing returns of games which are about building decks from trading cards: At the start any new card is a great addition to your collection which improves your options. Once you have a big collection, a lot of the cards you find are ones you already have, or are just minor upgrades. So if Card Hunter was all about extrinsic rewards, I would have grown bored by now.

But fortunately Card Hunter is a much better game, with much better replayability due to the intrinsic rewards of the tactical turn-based combat system. After finishing the campaign you get the option of doing adventures again with some handicap. And you can always hire new characters (currently either level 1 or level 10, with different cost). So I am currently playing an all-dwarf party from level 1 up. Dwarves are slow, but have high hit points, so I developed a strategy which goes well with that: I loaded the wizard up with Firestorm cards, which hit everything on the board regardless of location, including yourself. Due to high hit points, armor, and self-healing, my dwarves can survive that. But large hordes of small enemies are extremely vulnerable to that tactic. That leaves only the bigger mobs as problem, and they are much less of an issue for a dwarven party than the more agile and faster small mobs.

Even in the closed beta version I am currently playing, Card Hunter has a huge amount of content. Many different adventures, using different boards and different enemies. The AI is generally quite good, so that mobs with different abilities also act differently as a function of that: For example mobs with lots of range 2 spear type attacks will always try to stay at 2 squares distance from you. There is a lot more variety between two Card Hunter battles than between two combats in a typical MMORPG. Playing another battle is fun not because it promises another reward, but because it will be different, and maybe your current deck isn't good for the new challenge and you need to twiddle with it again. The intrinsic rewards go hand in hand with replayability. That feels a lot less like work than a game you end up continuing only for some extrinsic rewards.