DRV8846: Operational at VREF between 0 to 1 V, but accuracy is degraded

Part Number:DRV8846

Hi all

Would you mind if we ask DRV8846?

There is the description "Operational at VREF between 0 to 1 V, but accuracy is degraded." on the datasheet P4.
According to VREF between 0 to 1 V, what is affeced for?
VREF is used for Ichop, so does VREF between 0 to 1 V degrade for current limitation?

Kind regards,

Hirotaka Matsumoto