So based on the report, only those small and medium exchanges does not show their real volumes. I don't think this serves as a major problem in the crypto market when the largest and famous exchanges do report their actual and real-time volumes. People just need to use those if they don't want get stressed on this facts.
It is done by a small exchange so that people trust more in their exchanges. Usually traders are reluctant to trade in an exchange if the exchange has a small volume, because the amount of profit and the speed of profits are affected by the volume, it is not a major problem..