Absolute max supply for the IC is 12volt. Kingbright display is ~8volt@20mA.
Read somewhere in the datasheet that voltage difference has to be kept under ~2volt, otherwise the IC could overheat. So 10volt seemed the best option. Close to the IC's max, so regulated.
Could not find the voltage needed on pin19. The datasheet only states current.
And the drawings show a 100k pot between the IC's supply (pin20) and the curent input (pin19).
Opto isolaton seemed the easy way, unless you have another solution.
A simple yes or no is not going to help OP.
Leo..