Thanks for the discussion and feedback. One thing that I think you have wrong though is the concept of inflation. You write:

Giving out packs as rewards is a huge inflation to the system

But really giving out packs has zero inflation to the system. There are a set amount of packs that will ever exist (900,000 in the case of Beta) just like there is a set amount of Bitcoin that will ever exist. When we give out packs as rewards, that's us giving out some of those packs for free rather than selling them as added incentive for people to play.

If, however, we give out XP as rewards, then we introduce unlimited inflation, and this is exactly what we want to avoid. It also disincentivizes combining cards, which I don't want to do.

Ultimately, this comes down to the core difference between a blockchain-based game with scarce digital assets vs a conventional game. In a conventional game, of course we would give out XP through play, we would give it out left and right because we don't have any assets with values to protect.

A blockchain-based game, or any project really, is about scarcity and value. That's the main innovation that blockchain technology introduced - digital scarcity. So, being a blockchain-based game, I see the scarcity and value of the assets as the primary focus and I don't want to compromise that by adding unlimited inflation to the assets through XP rewards.