WTC can be utilized to buy and sell data, perform transactions on parent chain, or to create sub-chains with their own tokens (like ether is used to create ethereum - based tokens). (crypto-reporter.com)
All sub-chain tokens can be traded on the decentralized exchange of the parent chain, where the WTC is used as intermediary. (crypto-reporter.com)
One of the key ideas there is that each of the blockchains regularly store their current block hash in their parent chain so that users can challenge potentially invalid child state transitions in the parent chain.» (links2exchange.net)