The data is extracted from CoinMarketCap. Simply by removing all "stablecoins" and adding up only U$ volumes, you arrive at 1.6% Bitcoin volume traded in actual cash. Everything else is stablecoins.
What do you think about this? Seems like obviously something's wrong here? Why are stablecoins even being called dollars? Makes no sense. This is a time bomb and gonna explode at some point.
There are certain benefits of using stablecoins and let me explain those benefits without going through the debate of backed up stablecoins. Real USD volumes are less for certain reasons as mentioned below,
1. It requires a bank account and the transfers can be tracked by the regulatory bodies.
2. Most of the crypto traders prefer to remain anonymous
3. Stablecoins are easier to handle than real USD
A majority of the traders don't prefer to go through all these hassles. They just need something which can be calculated according to the value of USD. Stablecoins just filled up that space!
So inclusion of stablecoins is the right way to calculate USD volume because they are just the digital representation of USD. Actual USD handling requires a lot of hassles and your choice of exchange becomes limited!