Because it's almost solely traded on their own exchange (93.55% volume) that only deals with BCC. They can make up the numbers as they please and nobody would know.
They can send whatever numbers they want for the price and volume to coinmarketcap through their API - which is the only requirement.
I'm not sure why coinmarketcap is dropping the ball here both with the fake circulating supply and listing the untrustworthy exchange.
It's like bitcoin with 1/10th the fees... it's not totally useless. Anyone who wants to seriously use a crypto to transact, rather than invest, would be better off using BCH for the time being.
BCC is in question, not BCH. And Bitcoin had near free transactions... when it wasn't used. A fee market is necessary both to combat bloating the blockchain with millions of dust transactions and flooding attacks. If BCH would be used, it would have much higher fees.