With a apparent speed indicator and an instrument that will give you "True" wind direction and "True" wind speed it is a much more useful device.

That use is not only for the "instant" condition, but as much for a sense of the trending. (e.g., is the wind veering, does it pick-up when it shifts, etc.)

Like anything else, there is question of whether it's essential which is relative and personal -- but I find it informative and useful.