Limiting rewards makes sense, but with the current system no one plays because the rewards are tiny, so we could expect that people would stop after they cap out, and it can still be abused with alts. It's sad that people who can't just have fun earning their rewards have to ruin things for everyone...
Maybe people would play the tourneys for no reward if they had more "themed" events where there's some special twist on the matches for that tournament, like the rotating game modes a lot of MOBAs have these days
