I'm not sure I understood it correctly, but betting odds can change drastically? Can then change after I make a bet, or is my bet locked it at a time I made it?
This system uses parimutuel betting, so odds are not fixed until betting ends.
You can see the current odds when you're placing your bet, but those odds may go up or down a bit, depending on how people after you bet. Everyone gets the same odds once betting ends.
Parimutuel betting is a poor system for sports betting. You will want to do fixed odds betting.
Fixed odds betting relies on two-party contracts and there are plenty of existing systems for that. For this, we used a more decentralized design for parimutuel betting.
With all bets placed by users, there's no need for a house. Bets are placed and paid out at the protocol level, so you always maintain the private keys to your bets and never send coins to a trusted intermediary.
By eliminating the house edge / vigorish (typically 10%) we intend to attract bettors with significantly higher payouts.