Well, sport betting is not, and it is partly skill-based.
Sports betting is vary skill based. I played at one of the free ad supported sites for 2 or 3 months placing anywhere from 1-10 bets each day. (Ref http://www.sportsplays.com/liquidxskin.html Non Ref http://www.sportsplays.com It's not bitcoin based however it is 100% free and they do payout according to the forum) The end result was a 30.2% win rate and $0 balance but hey it was free money so no big deal. On sign up you get $1 and SP replenishes the account with $.50 every bust. Anyways, the point is sports betting takes skill. I started the experiment expecting 50% win rate (betting the favorite on tennis and baseball) but sports are not random like most online gambling.
I've registered with your reflink.
I hope it works as well as you say it does