because comunity Gbyte user is low, and Gbyte price is very high, and not big exchanger same poloniex
Give it time to grow. Now you can get free GBYTE from Airdrops - just link your BTC address. And if you want so speculate you can also buy some. This currency/technology is very new, but the dev is quite promising and delivering many wonderful features. If this continuous, then byteball will increase users and use cases.
Again - give it some time - join the Airdrop and be patient.