[anonymouz]

CryptoKitties seems to work because all the game logic is on the blockchain. But for a more involved game this is not feasible. Whenever you have to interface with the outside world you have a trust issue there: You need to somehow trust the correctness of the data put on the blockchain in the first place. This is the same problem where smart contracts break down when they concern stuff outside of the blockchain.

E.g., if I wanted to, say, give out blockchain-diamonds to Minecraft players when they mine diamond ore in Minecraft, I need to somehow be able to trust that when a server reports "player X mined a diamond on my server", that this is actually correct. Whenever you you have an interface to the outside world you get these kind of trust issues. And then you might as well go with a centralized or federated solution, since the trust issues are the same but a federated system is much more efficient.

Same for the indies: To make the economy worth anything, it can't be trustless in the sense of blockchain. Indie company A must somehow be sure that indie company B (or anyone else) isn't giving out rewards for cheap. At this point you might as well build a federated system built on public/private-key cryptography and save yourself the overhead of a blockchain.

As for the tournament prize: I don't see what the blockchain accomplishes over an email/piece of paper/whatever saying "Player X won tournament Y" that is PGP signed by the organizer of the tournament. It is even more resilient than the blockchain (the receiver can keep and show it as long as he wants), you can send it to whomever you care to, and you can copy it as often as you like.