You can use the native Bittensor wallet to play in the Bittensor ecosystem.  

The exchange is a DEX within the Bittensor network.  It’s a closed network.  The subnet tokens cannot and will not trade on any other exchange or network besides Bittensor.  

You MUST buy $TAO tokens in order to participate in dTAO and buy the subnet tokens.  

This creates additional demand for $TAO which gets locked out of circulation when you swap it for dTAO.