This is not a correct statement
The bri_inc command that increases or decreases brightness also works as stop when sending the value 0
That is how Philips Hue does it when you press and release the + or - buttons
Sending many small increase or decrease messages floods the narrow bandwidth zigbee channel. Correct way is to put lights in a zigbee group, start increase or decrease the full gang with one message to the group and send the stop when releasing button
I do not know the syntax for ZHA but for Deconz look here